Ya, I wouldn't suggest buying through amazon unless you are incredibly thorough about making sure you get the right edition and don't plan on dropping or adding classes. They can take awhile to get and they are just a pain to return. I usually buy my books from the campus bookstore, but that definitely isn't the cheapest route to take - just the easiest.
what classes do you have? i usually buy from bookstore, but that's not cheap. this semester I bought from amazon, but i don't really know if i have the right editions for some. i bought one i didn't need, too. so blah. haha