You should try looking in your local Craigslist too, they sometimes have it for cheap. Also look at this guide for games once you have one.
http://vsrecommendedgames.wikia.com/wiki/PSP
If it's too good to be true, it almost always is.
That said, I did buy a broken PS3 off eBay for $50 a while ago. Turns out all it needed was a little bit of cleaning inside, and now it works.
I've had good experiences ordering from eBay. The ones with a lot of feedback are located in Hong Kong, so it takes about two weeks for the packages to arrive. But they came as described.
I bought this repair kit for my 360 six months ago to fix it from RROD'ing. It worked fine until tonight, and now it won't work at all anymore. Are there more reliable ways to fix my 360 to keep it from red ringing?