Any advice on buying quality vinyl

Discogs is the database for sure, but ruined by careless/dishonest/ignorant users IME. I have hardly got a satisfactory deal from them, only 5 % at most have been exactly as described, unfortunately. The biggest problem is lack of photos of actual albums in question, and that is the main source for confusion and abuse, just take a look at feedbacks ..... incredibly lots of confusion there. And no buyer protection whatsoever when ripped off.
For me personally eBay is more safe place to buy used vinyls, nevertheless. Like it has always been. Of course, you should be very very careful before you hit the button. It´s your decision, your money.

^ Great story, well written, ending up with an über Cleaning Machine: ) Very funny indeed ´cos you never know what lurks there inside the groove on secondhand/used/virgin records and it´s always recommended to clean your records, old and new before playing.
I use US in the end and proper rinsing and drying. Use as little chemicals as reasonably possible with US, very little alcohol and just some drops of water surface stripping agent Tetenal. At least twenty minutes in US bath.
My method is quite simple, first US with my cheap BAKU, drying the wet record with (reasonably cheap) Moth. And I always brush the stylus before each side.