As an additional note to Bpoletti's post, I have found that when buying used vinyl, sets offer a combo of both great value and good condition. YMMV, of course, but in my experience, most of the sets I've bought are in better shape than the single LPs. Perhaps their owners cared more about preserving their purchase, or they just were too bothersome to pull out of the box, but they are rarely beaten up.
Don't forget to look for local record shows, shops and yard & estate sales where you can visually inspect the records before you buy.
Don't forget to look for local record shows, shops and yard & estate sales where you can visually inspect the records before you buy.