biology book to sell?

I seriously doubt that you're going to get a used one for cheaper than $50 (textbooks are expensive and that one's under $100 full price new). Unless you can find somebody at your school who's already taken the class and has a book to sell cheap. Amazon has it for $58 used. You can also buy the previous version, which is a lot cheaper and won't be that much different because it's that much older. It's at the URL below. But if you use a previous version, you may need to do some tweaking with reading assignments, etc because the pages may not be exactly the same. Keep that in mind. You could always ask the instructor if it's ok.

Do you have any type of used book stores in your area? One place to look. Does your school have a used book store?