My girlfriend got an OEM Logitech Quickcam Pro 4000, for 45 dollars. ( 100 dollars on Logitechs website ). It's a very good, clear, webcam. That was about 9 months ago, and its still working fine. She got it from some website from
www.pricewatch.com, so I'd suggest that.
The webcam scorpion suggested, they're not too bad of cameras, but they quality of them are very bad. 2 for 65 bucks or so isn't too bad though.