When shopping at Sim Lim Square, it'll be wiser to move from shop to shop and compare the prices. In addition, do NOT compare within the same level.

In addition, I would personally NOT reccommend buying any IT gadgets from 1st / 2nd floors (where all the 'black' shops are located) unless you REALLY know they're legit. Eg, Song Brothers, Merdeka, Epic Centre...

Lastly, please please please, bring a knowledgeable friend along to buy IT gadgets or at least have someone on the phone whom you can call and ask for help.

1. Do your research: Before you bargain for an item, make sure you know its market price. You are less likely to be ripped off if you know what the recommended retail price is.

 2. Goods and Services Tax (GST) scams: Not all shops have to charge GST, only those with revenues of more than $1 million a year. If you are not sure, ask to check the GST registration number. Also, ask if the quoted price includes GST or not. Some retailers sock it to you only at payment.

3. Check the warranty: Insist on the manufacturer's warranty and the official receipt. You will need this if you want repairs done during the warranty period.

 4. Check your items: Shop owners may sometimes remove items that originally come as a bundle, so they can offer it at a lower price. When you commit to a deal, be sure to check the items that you have paid for.

 5. Insist on testing the product: Because of some shops' no-refund policy, you should insist on testing the product before taking it home. Ask about the exchange policy as well.

 6. Check the price: Ask for a detailed breakdown of what you are paying for.

 7. Ask for freebies: If haggling fails, ask for free gifts instead. For example, when buying a hard disk or laptop, you could ask for a free cover in lieu of a discount.

 8. Shop around: Browse and collect brochures before settling on a shop. Do your own comparisons to find the best bargains. Don't be shy! With so many shops  offering the same products, you can take your time to make a choice.

 9. Don't be intimidated by jargon: If you can't tell your SD from SSD, get help. Those who don't know what they are buying are more likely to feel cheated after making the purchase.

 10. Shop at STARetailers: This programme by Sim Lim Square Traders' Association ensures that shops keep to a certain standard of quality and service. STARetailers are indicated on posters and signs in the mall.

 11. Go on week days: The mall is less crowded so you have more time and space to explore your options.

 12. Know your way around: The first and second floors offer mostly consumer electronics such as digital cameras and plasma television sets. The third to sixth stories are dedicated to IT products such as software, computers and games.

 13. Beware of imitations: Some products are imitations although most salespeople will tell you if a product is genuine or not.

 14. Second-hand items: If something is too cheap to be true, it probably isn't true. Ask the sales staff if it is a secondhand or display item, which is often marked down.

 15. Be a serious shopper: Shopkeepers say some customers bargain for the fun of it. Be sincere when you negotiate prices. Sales staff will be more inclined to quote you a better price if they know you are a serious buyer.

Check these video out for scam prevention.

 No pricetag scam
Most of the shady shops put their products without price tags. Obviously products without a pricetag are subjected to varying quotes from the seller. The seller normally will asses how stupid the buyer in before quoting a price. Remarks like ‘I am not familiar’ or ‘I am tourists’ will definitely result higher quote. In some instance, sellers will try to convince the buyer that the price they offer are the best by making the conversation seem secretive or uncomfortable for the seller.


Goods and Services Tax (GST) scam
In this scam, sellers would first quote potential buyers a price and then just before the buyer makes
the payment they would tell the buyer that they’ll need to pay 7% GST on top of the quoted price. Most people would take this as something that they have no choice but to pay for. However, this is not true.

GST registration is not mandatory for all shops in Singapore; GST registration is only mandatory if the turnover of a business entity exceeds S$1m annually. A proper GST registered retailer is also required to quote prices inclusive of GST during a sale and at the same reflect their GST registration number prominently on the sales invoices along with the exact amount of GST paid.

 More unscrupulous shops will quote GST that is differ from the norm. Like 8% or 9% accounting for random stuff they make up themselves. Some shops even purposely miscalculate the amount of GST that buyer need to pay.


GST Refund scam
This scam will usually be employed together with normal GST scam. The seller will tell buyer that they can claim their GST back at the Changi Airport, Harbour Front or even Checkpoint.

 Most people do not know that tourist can only claim GST back at Changi airport. Not even at Harbour Front. And thats assuming the GST itself are charged from valid shops with proper GST registration number.


Counterfeit scam
This normally applies for software, but also to hardware at times in case they deemed the buyer to be stupid enough. Some Sim Lim Square shops were busted by the police for selling counterfeit copies of Microsoft Windows.

 Many stores are also selling counterfeit copies of the popular Apple iPod music players. They have the same packaging, material, shape and even colour choices. But what’s inside of these chinese “MP4″ players are nothing like a real iPod. I do not mind if they are honest with the counterfeit, but some unscrupulous shops sell the items as original products.


Missing component scam
In this scam, the seller would quote the buyer a price that seemed awesomely cheap or too good to be true or both. After the buyer makes the purchase, the seller would then ask the buyer if the buyer would like to purchase accessories that would otherwise have been bundled with the product ranging from stupid stuff like straps to critical stuff like charger, battery and data cable.


“Top-up” scam
Many scammy shops usually do not allow buyer to test a brand new unit unless the buyer is committed to buy it. In this scam, the seller would convince the buyer to purchase something that he/she would later find to be unsatisfactory (e.g. faulty or of lower standard or incomplete set) and then offer the buyer a top-up for a pricier product.


Bait-and-Switch Scam 1
This is probably one of the most popular scams around. In this scam, the seller tries to lure the buyer into his shop by quoting a super low price for items that buyer wants – say Item A. When seller and buyer negotiate, the seller starts to make Item A sounds like a lousy products and start promoting Item B which buyer is not familiar with at ridiculous price. During the process, some shop used some ‘tweaked’ equipments to demonstrate how inferior Item A is.


Bait-and-Switch Scam 2
In this scam, the seller and buyer negotiate for one item, but the seller delivers another. For example, the buyer is seeking a 16GB memory card, but is handed an 8GB card. If the buyer does not notice the switch before the money is exchanged, or the switch is done after the money is exchanged, the seller will pretend that the negotiation was always for the inferior product. Even if the buyer has not yet left the store, the seller
will refuse a return or exchange.


False Warranty 1
During negotiation the seller tries to give impression that the item is indeed covered by manufacturer’s warranty while in reality the item you are buying are grey market without official warranty. Upon payment, buyer may or may not be notified that the warranty is actually shop warranty and not manufacturer’s warranty. Which leads the seller to …


Hardselling (Extended) Warranty
The seller starts by trying to convince you on how ‘fragile’ / ‘valuable’ / ‘crappy’ your purchase is especially after manufacturer warranty expired. The seller could further comparing manufacturers warranty with piece of worthless toilet paper. This is often done after they are pretty sure you are going to buy the item (or worse… have bought the item).


False Warranty 2
This happens to some friends of mine who bought Nokia handphone from one of the seller in Chinatown. Everything looks fine until the phone broke down few months later. Upon visiting Nokia care, my
friend was informed that the phone he bought was not covered under warranty and the warranty card that he owned were not for that phone – regardless whether it was an original copy or not.. Note that handphone’s warranty card usually contains IMEI number of the phone it covers (google ‘IMEI number’). Mismatched IMEI number usually results in warranty not being honored. 


 
Oh yeah… forget about refund. No such things for shops you normally found in Sim Lim Square, Lucky Plaza or Chinatown. Thus before making payment, buyers should insist that they test the product. If it’s a product cannot be tested
(such as RAM or hard drive), make very sure that it’s covered by a
manufacturer’s warranty, not the store’s own warranty!

Acting on the false belief that Singapore has extremely low prices on electronics, tourists flock to Sim Lim Square to snatch up the latest cameras and computers. 

Some unscrupulous salespeople are unable to resist the easy sales and take advantage of tourists who assume they’re getting a great deal.


Most of Sim Lim’s vendors are reputable, but you can defend yourself from the rip-off artists by following these tips:


Compare prices
Before you make a major purchase it’s a smart idea to check the price at other local shops and even in your home country. Prices on new brand-name electronics really don’t vary that much and Singapore is definitely not the cheapest place to shop. I got a much better deal on my DLSR camera in Canada and the warranty is longer!


Information is power
It’s easy to use the internet to check a product’s suggested retail price and even print out information about
what you plan to buy. S$400 may seem like a great price for a digital camera with accessories, but not when you later discover it’s an old model and suggested retail price is now S$300.


Confirm the total price
One of the most common complaints is salespeople who add surprise 'unlocking fees' to the bill for phones and video games. These fees are often a scam.


Be wary of fakes
I don’t recall Apple launching an iPhone nano, but I have seen one at Sim Lim Square! Though police raids have made them rare, fakes do exist.


Don’t be charmed
The shops on the first floor are known for specifically targeting tourists. Anyone who shouts at you across the mall about special deals ‘just for you’ probably doesn’t have good intentions.

http://forums.gameaxis.com/showthread.php?t=1499020

http://www.sgclub.com/singapore/bad_service_sim_153590.html

http://forums.vr-zone.com/pc-console-games-garage/133146-beware-game-shops-sales-tactics.html

http://forum.gameaxis.com/showthread.php?p=21635833

http://www.asiaone.com/Digital/Features/Story/A1Story20090514-141410.html

http://www.clubsnap.com/forums/showthread.php?t=192394

http://www.singaporeexpats.com/forum/ftopic56971.html&sid=2bb1f2a6cf6c60b558035aed8f9338eb

http://forums.vr-zone.com/world-news-singapore-affairs/418426-news-tourist-cheated-thrice-one-day-sim-lim.html

http://forum.lowyat.net/topic/1732117/all

http://singaporeseen.stomp.com.sg/stomp/sgseen/this_urban_jungle/974594/sim_lim_shop_charges_me_661_for_ps_vita.html

http://www.complaintsboard.com/complaints/mobile-apps-pte-ltd-02-72-sim-lim-square-singapore-188504-c580285.html

http://talkback.stomp.sg/forums/showthread.php?t=28013

http://www.scamfound.com/f13/pc-geeks-simlim-square-overpriced-items-rude-staff-165699.html

http://www.moneysmart.sg/frugal-living/5-money-saving-ways-to-buy-electronics-in-singapore/


It is hard to close these shops despite the complaints because they will register the shop under another name and owner. That is why it is recommended that one should only buy game console from established or reputable shop. The best game console shops are those that has repeated customers and grow by word
of mouth, and will strengthen their company brand through good value for money and excellent customer service.

Remember these rules !


Rule #1:     
Never buy gaming console/games in Sim Lim Square. Unless they are recommended by friends / relatives.



Rule #2:     
Remember Rule #1 because it is so important. No need to spend money to learn the lesson because many people have already done so for you.



Rule #3
Only buy from reputable shop who shop name is a well-known brand.  As to what game shop is reputable in SLS, I don’t have the answer since generally many in internet forums speak negatively of game shop in SLS. Probably can treat Rule#3 as non-existent then.

However, if you still wanna buy gaming items in SLS, make sure that


Rule #4:     
Whatever you buy there, double check the purchased item before you step out of shop. Open up any item even if it is “cheap” accessories, battery or anything. Request to test if possible whatever you buy at the spot even if the shop is reputable or grant 1-to-1 exchange within grant period. Most importantly, check your receipt properly (eg date, serial number, item list)  and make sure all items are listed. Never trust what they say (even if they say that the item is already in the bag), only trust what you see.


 
Rule #5
Only buy the item you have originally in mind. If the item is not available, walk out immediately. Do not let the staff recommend other items because they will (definitely) mark up to high price and also “force” you to buy having told you that they already prepare the receipt and make the order.


 
Rule #6: 
Do your homework. Don’t ever buy any expensive item on impulse else you find the most ridiculous reasons ever giving to you just to rip you. There are many affordable internet cafes around SLS that cost less than $2 for 1/2 hours, and you get use it to google the item and the name of the shop you about to buy from.


 
Rule #7: 
If you get ripped off, take as lesson learn. Complaining to Police and CASE is unlikely to help much because chances is that your predicament isn’t new too and that particular shop very likely to be already blacklisted. Those shop owners may even challenge you to call the police or report to CASE. You are buying and patronizing those shop with your eyes wide open.

The following are some of real common examples of how a customer may get ripped
off. These are just tip of the iceberg.

• Quoting price without GST. You realize that without a price
  tag, they are free to quote whatever price they want.  For example, if you ask
  one of the staff and the staff quote you a price with GST inclusive, and the
  next moment if you are serviced by another staff, the price quoted is yet to
  include the GST and worse, they pretend to keep silent on the “discrepancy”
  until they have written a receipt that add “extra” GST. By then, it is too late
  to reject it as they say it is impossible to cancel the receipt. You will soon
  find that you are surrounded by their “gang” when you start arguing with them.
  


• Removing the item. Assuming that you purchase many items
  from them, they will place the items into the bag before you after you pay them,
  and distract you with other things while in the meantime taking a item out of
  the bag. The moment you walk out and find out that a item is “lost”, it is too
  late. They insist that they already put the item right before your eyes and that
  you have “lost” them. Therefore, always recheck the items again before them
  prior to stepping out the shop. Call the police immediately if any item is lost
  they refuse to acknowledge that because this is thief.


• Modifying receipt. They will write a receipt before you
  listing all the items you purchased and purposely withhold the receipt. Those
  items will be displayed before you. But once you paid them, a new receipt will
  be issued with lesser items and higher item pricing, and once you unknowingly
  take the receipt without checking (since you have witnessed that they have
  written all the items in the receipt in the first place), they will put those
  items from new receipt into the bag. When you question them why they didn’t put
  the remaining item, they say that it is not in your received receipt. asking you
  if you want to pay for those remaining items.


• Purchasing in bundle. If you are buying a item that sound
  too good to be true, you realize that you end up paying more because they will
  add some items that mark-up ridiculously high without telling you that the item
  you purchase only offer in bundle. They will quickly hand you the receipt
  without explaining that the deal come in the bundle. Once the receipt written,
  they will display hooligan behaviour, intimidating you if you reject the "deal”.