I have 2 kids that just graduated from college in May (yeah). I found a place that rents books by the semester. The website is
www.chegg.com. I think I saved around $1000 for the 2 years that we rented books. It may be worth it to check them out. They were buying the books from the bookstore and at the end of the semester selling them back but were either getting very minimal money back or the professor were changing books the next semester and the bookstore would not back them back.
Also you said you needed to get some Microsoft software. You should check with the bookstore or technology department. You should be able to buy that software for $20 or so. Microsoft has some kind of deal with the colleges.
Good luck with the book buying and with college in general.