[TPA85]

I got accepted into grad school (YAY! and OMGWHATDIDIJUSTDO?) and I'm looking into the cheapest place to buy or rent books. When I finished undergrad, Chegg was just becoming a big thing so I've never gotten books from anywhere other than the university bookstore.
So far I know of Chegg, e Bay, and half. com.

Any other sites I should be looking into? Alternately, are there any sites I should avoid?

Thanks!