This is the mecca for electronic gadgets. If you can think of anything this place probably has it. Another mall with similar reputation is Funan mall but now-a-days I just skip this place in favor of simlim. Funan is just over priced as it has big multi-national chain stores. If you really wanted to shop in places like this, then shop at home.
Sim Lim has six floors full of shops selling electronic goodies. Some dodgy and some not so dodgy. When you get there for the first time its just mind boggling and my advice is to take the lifts straight to the top and circle down floor by floor.
There are some tips when shopping for big budget items.
1) Pick your item / model number before you get here. If you ask the store attendant for his recommendation then what ever he has on hand is going to be the best. Alternatively go and talk to the shops in funan and then buy from simlim.
2) Do not under any circumstances purchase accessories that you don't already know the price of. These will be overpriced and you could probably purchase them online cheaply.
3) Tax refund. Only some stores participate in this and make sure you ask them and get the appropriately completed forms from them. If they cannot give them to you then either walk away or understand that you will not get the tax refund at the airport. There are only two tax refund schemes so read about them online
4) Make sure you check all items before part with your money
Bargaining is the best part of visiting simlim. Just work your way from store to store and ask them to give you their price and then mention what deal the other store is offering. This tends to drive the price lower. Also make sure the number they give you is "inclusive of all taxes". Some stores will give you one price now and when you go back they say it was missing the tax. Stay well clear of them.
Once you have found a price you like ask them to show you the goods. Then inspect all items and if you are happy with them part with your hard earned cash. Yes cash, plastic cards are fine but then be prepared for surcharges which vary from store to store.
Some of the stores i've come to rely upon over the few years I've been travelling to Singapore and SimLim are:
Alan Photo - for cameras and the like
Bizgram - computer accessories
Furwell - computer accessories
Here are some links to get you surfing
Sim Lim Sq
Online price lists
Just a short walk east along Rochor canal road is New Bugis steet where you can buy cheap clothes and tourist memorabilia.