Good place to start looking for used Corvettes?

So I'm looking at purchasing a used C5 since the current prices have been dropping, but this will be my first time buying a car. Any advice on where to start or what to look for?

So far I've seen a really attractive deal for a 2002 base model, and a decent deal for a 2002 Z06, both were under $16K

Ideally $10K would be my max, but if I can get some trade in value for my current car I may up my budget to around $15K