I too have had good experiences with BF (and CR) members, buying & selling. As the OP pointed out, this isn't an expensive hobby at all. Because the low dollar value of most of this stuff, I have given a bunch of things away (or charged only shipping), and received a similar amount of stuff for little or nothing. Sometimes quite nice and rare things. The only time I can remember being disappointed (other than getting in too late to buy some little jewel) is when I tried to buy a pair of pedals from a BF guy. He agreed to sell them to me, but never got back to me when I asked what form of payment he preferred. When I did catch up with him, he told me he'd sold them locally because it was less hassle than shipping them. Annoying, but no harm done.
Other than that, folks here have been trusting, and have never violated my trust in them.

I hope I haven't forgotten to thank anybody, especially those of you with blunt instruments.