I've got an Antec 500W power supply, I forget what type, that has two fans on it: one inside the case and one outside. The outside one isn't running, which I'm guessing is bad and means I need a new PSU. Anyway, I'd like something uber cheap. I found AMD brand ones on Pricewatch for $20-ish, but I'm not sure if they're any good.
http://3btech.net/chdufan650wa.html