For everyone concerned about books, I guess the Kindle versions and used ones on Amazon are an option. But really (and I'm not promoting it in any way), I keep receiving these emails from a book rental company that allows college students to rent ANY book by week. And they have some deals for newcomers and referrals. I don't know how reliable it is, but it sounds pretty good for books that are only required for a couple of weeks or a month.
I wonder how that works and if it’s legal.