My daughter, when a teen, went nuts over the pop music in the early 60s. I checked prices recently and some are worth quite a bit- or would be if they hadn't been played to death, and mostly left out of the sleeves and picked up scratches. The sleeves, many of them, are in very good condition. I have helped a friend improve the value of a few in his collection by giving him covers where his were water-stained. Never throw a good sleeve away if it is from a first issue.
I have a mystery novel that catalogues around $1000 with the dust jacket. I don't have the jacket so it is only worth about $15 max. LPs are the same, as MTed says.
dwditty re-posted the gemm.com. I recently got a rare one from them, fine condition, too. They are worth trying if you have the money.