I really don't know why they cost so much. It is highway robbery!
I have 5 classes this semester and would have forked out $850.00 if i had purchased my 4 books that i needed at Purdue's bookstore.
I went online and bought my books on half.com and amazon.com and saved $500.00.
As long as you know the ISBN# you can always look for better deals online and are not at the campus bookstores mercy.