Tina,
Try to get them together into COMPLETE SETS as much as possible before you sell them. You will get a much better price that way, especially for MNH. While Scott will list prices for individual stamps in those sets, that is primarily for dealers when they sell -- protection/incentive for them to break a set when necessary. When buying, broken sets get an extremely small fraction of catalog value from dealers.
Patience in assembling complete sets from your accumulation will pay off in the long run.

k