From the Toys section:
Amazon has Crucial 2GB 667 Mhz CT25664AC667 DDR2 200-Pin SODIMM Laptop Memory on sale for $19 with fee shipping. This is the lowest price we’ve ever seen on this memory, let alone from a name brand like Crucial and a retailer like Amazon. This memory can be used in Intel Mac Minis, iMac and most pre-Unibody MacBooks and MacBook Pros. Check here for a compatibility list. Double check that your system is compatible before buying.
It also works in many models of the popular ASUS EEE PCs.