The best ACT books/tips?

I have decided to take the ACT test in October,but I have rarely touched a book nor taken a practice test. Does anyone have tips that could help me prep? I am especially worried about math because I have not learned some of the material that is tested on the ACT such as Algebra II.

P.S. I am currently a freshman in high school

crack act . com got me a 35. It’s free and gives you EVERY ACT TEST FOR EVERY MONTH.

Just realized that CC bans copyrighted test material. Buy the red book.