So id say 150$ is becoming common for an average textbook in my classes now. Idealy, textbook content would be free, possibly by some program set up by a university. Standard textbooks are way too pretty, and have way too many problems in them. An ideal textbook would be thin, possibly even paperback made from newspaper quality paper, and have content mostly online in a wiki format. It once again fits into the idea that proffesors shouldn't be teaching but facilitating learning by removing obstacles.