I find it odd taht we are constanly being told these items can't be found at bargain prices and instead get recommendations to buy inferior products.
Jason's got it right look locally and there's a surpring amout of excellent cameras that go for very low prices. I know I can pretty much guarantee to be able to get good post WWII folders for under £20/$32 with reasonable coated lenses. I have friends who sell a lot of cameras and photo gear on ebay and they have to source their items, it takes a bit of looking but it's fun and easy.
Recently I asked in an antique shop as I know they sell cameras as job lots and discovered they'd sold an M series Leica for £40 ($64) in good condition, they realised too late it was probably worth considerably more but they'd still made a profit as it had come froma house clearance.