Rarely do I get something just to hold on to it like a collector would. Some people just come naturally at bein' a collector, like my Bubba. But truly, collecting can be a good thing or a dangerous one. They have already done the dirty work necessary and have scored the deal you are looking for. Unless they're goin' outta business or something.
Flea markets put on by churches are also great.
Non-commercial flea markets put on by colleges, non profits are also dandy places to score trash. Estate sales are good, too, but you gotta be careful because many estates hire a management firm to run the sale and you can't generally dicker. Oh yeah, you must dicker. Then attempt to get a deal from the Yard Sale Proprietor. Likewise, if you gotta bunch of guy crap, go ask his old lady the same.