Folks, play nice.
half.com will save you the most money, and still be trustworthy
someone named pervert is thanking someone named badboy for a enjoyable night?
You are running into one of the main money making aspects of higher education. The prof's are confronted with publish or perish and the easiest way for them to accomplish that and make money is to write the text they want to use in their classes. They have a "captive" buying population and doing a rewrite or modification to the text each year means they still published and forced you to buy another new book as used ones won't be compatible. Yup it IS a scam and is not only accepted by the colleges but encouraged.
At my University, a professor cannot take any profits from a book he/she authors and assigns to a class. I find the bigger issue is apathetic professors, who don't even pay attention to prices. They just made some changes where publishers are required to release what changes were made in new editions and I believe there was something about having the price up front, fostering more competition. My intro to psych prof actually cared, put two publishers head to head and each continued to lower their price, eventually he found that he could just have the university printing service print it for $15 and sell to students for $22. That was a huge different to the $120+ the same books were originally at.
when I was in school in the early 90's I was spending about 750-900 dollars a QUARTER for books because all the classes I was in were from the medical school. I was taking classes for Kinesiology and Excercise Science as part of my major to become a certified CSCS (strength and conditioning coach) and a minor in sports administration management.Talk about a PITA because there was all kinds of lab books and other crazy things that we needed with working on cadavers and body parts.