When I was in school, I would often goto the teacher and say something to the effect of "Hey, I won't want to spend $150 bucks on the new edition of this book... since I doubt that much has really changed in this class, is there anyway that I can use the last edition, which was published 2 years ago, and costs 35 cents on Amazon?"
It might be that teachers in Kentucky care a little bit more, or are even a bit more polite than others in the country, but, I never had an issue doing this. If nothing else, I would buy the books used on Amazon.com, rather than at the book store (which always inflated the prices).
Even if a teacher is un-helpful, it may show that we as a society are screwed, since students will often be willing to spend thousands of dollars to take a class, but are unwilling/unable to buy a book for it, costing just a few hundred dollars (small by comparison). A lot of times, I get the feeling that people just don't want to spend the money, when they actually can; it has just become so acceptable to blame problems on money, that everyone seems to do it.
Food for thought, from somebody that was in college a few years ago...