This is my first year of taking AP classes and I'm currently taking Euro and Bio. So far I bought crash course for Euro and plan to buy PR along with it. Then Barron's for Bio.
I just read about the change in the Euro exam for 2016 which is after mine, but my question is, do prep books become useless once the exams are revised?
I heard how brutal the Bio exam was after the change and how none of the books prepared for it. My family is tight on money, so I want to be really careful in buying the right books. If I buy the newest version of the PR book for Euro, would it be really unhelpful for the new exam? I was planning on selling to a friend along with my notes or giving it to my cousin who will also take the new one.
Should I just buy a cheaper, older version of PR? Is there much of a difference?