It happens occasionally. There are several reasons to why you may not have received what you wanted for your books. Your professor re-ordered the book for the next term. We already have a gazillion of 'em in our bookstore, so we can't use them here. It isn't needed here, but it is needed on other campuses.
Demand determines the value.
The new edition is in so the old edition is out. Your book looks like it has been through a tornado. Textbook prices are determined by the publisher and are affected by two factors. High printing and marketing costs, frequent release of new editions and other expenses contribute to the cost of textbooks also. Most textbooks are ready to be purchased approximately a month before classes begin.