If you have the patience to sell them yourself--could take a VERY long time--you'll get more money that way. If you just want them gone but don't want to throw them away, HPB is a good option. When we lived in Iowa, we used to pick up a lot of free books from friends and family who were throwing them out, and we'd take them to HPB in Des Moines whenever we were in the area. We've gotten anything from $2 to over $100 for loads of various sizes. We got the most for recent textbooks (which probably cost a fortune new), and we got a decent payout for some old paperback books about French film.