That kind of thing is better purchased in record stores which, believe it or not, are still around. If you look "online record stores" up on Google, you can find many online record stores but the records are very expensive if you buy them online. Amazon also has many records for sale new and used. The issue with that is this: apart from being expensive, the shipping and handling also cost a lot of money unless you buy in bulk. You are far better off finding a record store near you. If you live anywhere near a beach with a boardwalk, the boardwalk usually always has a record shop somewhere on it with prices that aren't too high. If you can find a store somewhere near you that is not on a boardwalk, you are likely to get the best prices there. It is the kind of thing that you have to do a lot of searching for and it's a very good idea to compare and contrast different prices first.
Just look around and see what you find. They usually aren't very hard to locate and I find record stores to be extremely interesting to spend a few hours just exploring.
I really hope this helped you.
Ah, I didn't read the question correctly but it is basically the same concept for selling records. You can sell them on Amazon, some online shop you find on Google, or in a shop you find on the boardwalk or near you. To get the best payment amount, I would sell it online. To be guaranteed a legitimate transaction, you would be best off selling on Amazon. Just average the prices you see it going for in the condition the records you have are in and then post it for that amount. I'm sure Ebay would be useful too.
Record Theatre is a store we have located by us that buys & sells, not sure if they have a website online or not though.. or where else their stores are located...