@rvpiano Discogs site gives you opportunity to create your own collection, meaning to exactly catalogue it by edition and in the same time they provide you information about its resale value based on those same editions that were sold there.
You just need to read the number on your cd and with few clicks you will be ’building’ your personal collection, you will get the data for the lowest, medium and maximum amount for every cd.
Than, you may post all your collection for sale there, if you choose so. No trouble at all and when somebody buys any cd, you will get the money and than you send it.
I am still buying cd’s and the ones that are missing from my collection are sometimes quite expensive. Check the values of cd's in your collection, you might be pleasantly surprised. Best of luck