Kingston cards - Active Foto (level 4 Sim Lim Square, first shop on the left when you come up the escalator from level 3)
Transcend cards - Memory World (level 4 SLS, look diagonally right from Active Foto, it's in the back corner of the back row. Look for Valerie and say Jason from Cornerstone referred you for discount. 2GB 150 card should be $70-80 as memory prices change everyday.
Personally I use both Kingston (free with my D50) and Transcend (bought the 150x 2GB model cos significantly cheaper than Sandisk and Kingston's fastest cards. Also Memory World has fantastic service and support for all their products - true lifetime warranty.
I use their ram to upgrade all my office computers (Dell & Mac)- just give them your PC/Mac model and they can give you a guaranteed compatibility ram.