Depends whether they are actually "collectable". I sold a load recently when I moved house and the guy in shop said that there is always a market for certain artists, but other stuff that was very popular at the time has virtually no value.
Therefore if you have a decent orriginal copy of "A Night at the Opera" or "Harvest" or "Dark Side of the Moon", it will be worth more than a Whitney Houston album.
Also buyers are looking for little details that can make all the difference between wanted and trash. Examples inlude whether free goodies that were orriginally packed with the album are still included, and different labels on the record itself.
If you have a copy of "In Through the Out Door" where the magic painting on the inner sleeve has not been done and the brown paper bag outer sleeve is still there, then this makes the record more valuable than it otherwise would be........apparently