Buy.com has SanDisk 2GB Gaming Memory Stick PRO Duo for $9.99 + free shipping.
For maximum performance and to get the most out of all the advanced features on your PSP, you'll need a SanDisk Gaming Memory Stick PRO Duo card. With SanDisk, you will be able to save your game levels, listen to digital music, play your favorite video and download and store game cheat codes, characters and game skins. SanDisk game cards maximize your world of entertainment.This SanDisk Gaming Memory Stick PRO Duo card utilizes exclusive MLC memory and controller technology developed at SanDisk, meets all MS specifications and is guaranteed compatible.
SanDisk 2GB Gaming Memory Stick PRO Duo $9.99 FS 
