@grislybutter (now THERE'S a handle!): I'm lucky to have two local record shops that specialized in used LP's, and one antique mall with an incredible LP booth. I regularly find LP's from the 1950's through the 80's, in from VG+ to near Mint condition, usually priced from $5 to $10. And a coupla times per year Music Millennium in Portland has a sidewalk sale, where most LP's are $2! You have to dig through box after box, but that's part of the used LP game.
I bought and sold records in Goldmine Record Collectors Magazine in the late-70's into the 80's. It was a small community, the dealers very dependable as far as grading and condition. Ebay and even Discogs is very hit-and-miss, you never know what you're going to get. You would think Near Mint means Near Mint, but to some sellers it apparently doesn't. I prefer to buy in person, but there are some titles you are never going to find locally.