If you want to use ONE SOURCE and be secure and score REALLY WELL- almost GAURANTEED, use this one for free!!!
http://www.whfreeman.com/thelifewirebridge2/
It has ABSOLUTELY EVERYTHING you need to know for the PCAT. I literally came out of my PCAT and after using this as a study guide and the one's I wasn't sure about I quickly checked with this site and it had ALL the info.
Some parts of it are interactive so its kinda fun and has quizzes and everything!
It's based off an entire textbook so it's pretty damn thorough
Dr. Collins is also good as its made for the PCAT (P.S. still trying to sell mine, PM if interested lmao)... but this is a GREAT SITE!!!