I used to work at my university's bookstore (until it was shut down and I lost my job because too many people were ordering online) and now I work at the library.
First thing, I promise you the school bookstores aren't trying to rip you off. They really have no control over it because they MUST sell the books at the new and used prices that the publishers set.
Second, we have textbooks on reserve at our library and surprisingly, not that many people check them out. The business law book cost $250 by itself at the bookstore and there are four copies on reserve at the library that barely anyone ever checks out.
Another thing, I am a commuter as well and I actually find it easier to get the books on 3 hour reserve at the library. That way, I know I am forced to study and do my homework in those three hours, when at home I just procrastinate forever. Another thing you can do if you don't want to hang out at the library the whole time you do your work is photocopy the pages from the book and take them home.
Chegg is pretty cool because you don't have to deal with buybacks at the end of the semester. I got screwed my freshman year because the math department (NOT the bookstore) decided they were going to use a different edition on my $130 book next semester and the bookstore couldn't buy it back from me. (another mini-rant, complain to the professors about the prices of the books they choose, not the bookstore. Some professors do work really hard to make sure they're not choosing expensive books, some professors don't give a crap.)
Anyway, moral of the story, go with the library copies if you can, and if not go with Chegg. But don't be mean to bookstores cause they really can't help the prices haha