I sold all my vinyl this spring, made a couple thousand bucks. The guys at the record store told me that most of what they get is in too poor condition to be worth much, even if it is rare or interesting or collectible. There's a market for your old Beatles or Eagles or Fleetwood Mac albums, sure, but it's not a terribly lucrative one.
I was interested in cash rather than store credit, as I was trying to clear out my place so I could downgrade and move. The policy of the place I sold them was to pay half of what they expected to sell it for, in store credit, or one quarter in cash. The most I got for a record was about forty bucks, so they'd be selling it for somewhere around $120 to $150.
I could have made more selling them individually online myself, with an enormous amount of work. Say ten thousand rather than two thousand - worth it if you want to do the work, but not a fortune.
I've met people who assume that their warped and scratched copy of a Grateful Dead album is going to sell for thousands, and that's just not the reality. They might get ten bucks for it, and that's a good price. There are valuable albums out there, but you probably haven't got them.