Citizens of meh... Stamp collectors, help?

sohmageek thought this was worth mentioning said
2

So, it was "spring cleaning" day at storage (indoor unit I figured what else to do on a cold day that the MIL could watch @stitch. We found a boat load of old stamps, and other Americana to hopefully unload for a decent price. But I don't know the best way to do so. We aren't looking to squeeze every penny from it, but we don't want to sell the collection for $100 and find out it was worth thousands (most of it is from the 50's I think, but some of it could be from the 30's.) The point of it is for @stitch's college fund :)