I just found this website that can give you an open source version of your assigned textbook. Or if they don't have the specific textbook, there's still heaps of other info that might be useful. If you scroll down on the home page if gives you a list of subjects and then if you sign up you can add in your specific textbook. I'm still trying to work it out, but it's looking pretty awesome so far. And this is coming from someone who despises ebooks. So check it out.