Same here! We didn't have a comic shop, just comics off the spinner racks. The public library where I live though used to have a box of comics when I was a kid and they would let you trade one comic for one comic in the box. I would always dig through it for the Avengers, Cap or FF issues. Sometimes I would find the FF reprints in it and grab them.
They don't do it anymore. I think it's a shame. I've donated a LOT of tpbs to my local library and the guy that runs it has bought a LOT of tpbs and GN's for people to read. There's a whole section of comics. I think I'm going to ask him if I were to donate a big box of singles, would he allow kids to do that swap again. That would be cool for them.