THE MAJORITY of university courses require you to buy books for self-studying. Going to well known bookshops can give you a peace of mind when buying books, you know it'll be clean, brand new, etc. But for that, you're probably paying a bit much.
It seems that now, Amazon is the place to buy second hand books, nine times out of ten, they are in pretty good condition and for a fraction of the price. As a student myself, I've bought two books from here, second hand, and I can tell you, they don't look like they've been used at all.
For example; I bought a 'Teeline Wordlist' also referred to as a shorthand dictionary, for £4. In Waterstones, Ottakers or the university bookshop I would be looking at £18. You don't need to be a rocket scientist to work out the difference.
It also seems that you buy a book, thinking it'll last you for the rest of the academic year, this isn't always the case. You could pay out a hefty sum for a term, once that term's over, lecturers or tutors may require another. An idea, would be to keep your books in the best condition, and flog them when you KNOW you'll actually never need them again.