You all don't put up a book list in your dorms or the buildings of your classes?
That's what we used to do when I was in school. You list the books and the prices you are willing to sell your books for and place those lists in your dorms, all over campus.
Shoot, the only way I bought a BRAND NEW book was that I HAD TO. Otherwise, we learned to strategically plan. You take the class one semester, I'll take it after you.
Alot of people would rent their books to others.
Girl, I never used ALL my book money I was given on BOOKS. That extra money would keep me going "socially", if you will.

And I had EVERY book I ever needed.
BTW, this was before the internet.