I typically buy the textbooks I need from Amazon or eBay, especially the ones not for my specific program. For this semester, I'd found one of the books for one class on Amazon for 3.00, but it was a book on tape-not even CD! That must be the first edition of the book, published in 1999. There have been 2 editions since.
The other book, it was a tad cheaper to rent it from the bookstore than to purchase the current edition, so the day before semester break, I went and picked up both books, thinking it I wouldn't find better deals.
Of course, now that I rented these books, I found one on Amazon for 3.00-for the current edition, then found the other on Half.com for less than what I paid for the rental!
I suppose I knew this was going to happen, because if I hadn't opted to rent them, those other two never would have shown up!