If you live in Singapore you have to get used to wallets that weight more then your avaerage durian fruit. Carrying a couple of different currencies with you every day is just plain normal because you never know if you head to Malaysia for dinner or on some spontaneous weekend trip to Malaysia or Thailand over the weekend.
The Singapore Dollar
The Singapore Dollar itself is easy to use, nice money thats available in 1Cent (very rare) 5 Cent, 10 Cent, 20 Cent, 50 cent and 1 SD coins, followed by 2SD, 5 SD, 10 SD, ,20 SD (rare), 50SD, 100 SD, 500SD(rare), 1000SD(very rare) and 10000SD(super rare). The currency itself is quite stable although due to the current financial crisis it also is suffering some stronger then expected inflation influences.
If you need more detaield information about the Singapore Dollar and its History continue reading here Wikipedia: Singapore Dollar
Exchange Rates
For current exchange rates you can check this page which is real time updating and always reliable: www.xe.com
Where To Get The Most For Your Money
Now, back to your big wallet yu will sooner or later face the task of having to exchange money. The financial district is located around Raffles Place and I also believe you get the best rates just here. Don't make the mistake and walk into any bank office in in order to get your money changed, there are enough "street money exchangers" that will offer you better rates.
My favourite ones are located just left and right to the main entry of "The Arcade" facing Raffles Place. Very important, if you need small bills (as I usually do for travelling) ask them ahead if they have bills available, because it happened several times to me that they just claim not having any smaller bills even though im pretty sure they do. They usually have calculators on the desks so you can do your own calculations before approaching them. And count your money after you got it. It honestly never happened to me that something was missing, but better be safe then sorry!