Some Reasons why textbooks are expensive.
1. Technical books ie. Engineering are written by experts who are normally payed big dollars on daily basis therefore expect to pay more for books based on your major. Also technical books usually contain more illustrations and data which bring up the cost of production.
2. Publishers often release new editions of books for several reasons.
-Provide important scientific and industry updates which take place over time.
-To help thin out the market for used books and continue to make money.
3. College bookstore tend to have higher prices due to the financial aid monopoly along with the fact that most in house bookstores give a large cut back to the college.

If you are a College Student there are still ways to get around the high cost of textbooks. you can:
1. Buy your book online through price comparison websites.
2. There are also websites called textbook exchanges where College Students can buy and sell textbooks locally.
3. Book Rental websites, drawbacks can be the cost and if you will need to keep your books for reference in the future.
4. I also recommend to try and buy some of your books one edition behind as you can usually save around 80% of the cost and usually only about 10% of the information actually changes.