my first semester, when I bought everything brand new at the school bookstore, it was about $600.
after that, I learned a few tricks... don't buy a book until the professor actually starts using it (sucks to spend $200 on a book that the professor never quite gets around to using), check and see if the campus library has a few copies of the book (usually the case if you're taking any lit courses, and you can always photocopy a section or two at a time as needed... a lot cheaper than buying a whole text book that a prof only teaches a handful of sections from), find people on campus that took the course already and buy their book from them before they sell it to the bookstore, and when all else fails, shop on ebay for the book.