Other people have good luck finding nice bikes at Goodwill, Salvation Army, and pawn shops. I'm interested in road bikes from the '80's, and I never see a top 80's bike at those places.

So, although E-Bay is far more expensive than Goodwill, that is where I found the best bikes. If I'm looking for a red 1987 Dave Scott, size 58, I can search for it on E-Bay, and sooner or later, it will turn up. For about $200 more than Goodwill would sell it for.