As with anything used, you have to find reputable sellers. I never spend more than $25 on a first time purchase from a seller I haven't used before. Most sellers are concerned about their online reputations and I've had very few problems with the few records that were not close to being as advertised. I've purchased over 200 LPs on Ebay and until last month, never had a problem with a seller and Ebay handled this incident expeditiously and refunded my money.
I keep a list of favored sellers (and no I'm not sharing
). Well, I'll share one: Euclid Records. If anything, their grading is conservative and their service is spectacular. The records are rarely screaming bargains but you NEVER have to worry about over-grading.
I'd rather buy a great record at a fair price than a fair record at a great price.