What ap crash course/practice books do you recommend for the 2015 exam? Also is there any other source (like YouTube, a website, etc.) that you guys would recommend? And could i get a 4 or 5 by studying intensively just a week before the exam date? Thanks for any input!
Don’t EVER cram before the AP exam, especially if you’re planning to do it the week before; I highly advise against it. The AP exam must be studied and prepared for over an extended period of time. So the answer to that question is a big fat NO. I had a friend of mine who crammed for the exam a month before and he got a 3. He told me that if he didn’t cram, he easily could’ve gotten a 4. You will not get higher than a 3 if you cram; its alot of info that you need to know. Think about this: if you crammed for a regular test at school, would you get an A on it? The AP exam is likewise.
In regards to preparation, I’m personally using CliffsNotes AP Biology (4th Edition; newest one) and Barron’s AP Biology (4th Edition). Barron’s 5th edition recently came out, so I would suggest buying that. Try to get one of the newer prep books (after 2012) as they changed the test format in 2012. Multiple choice and free response questions now include application-based questions, rather than knowledge regurgitation as it previously was.
BozemanScience videos on YouTube is another amazing resource; he explains everything in an organized manner to make sure you know the material.
Good luck! 
Thank you so much!