act books

Princeton review is the only way to go

I bought the traditional act test book for the practice tests and just watched free youtube videos and got my score from 33 to 35

The princeton review one is really good- got my brother from a 26 to a 34.

"The Official ACT Prep Guide" is the best, the act book has test and includes 8 full-length official tests (online and print) and 400 flashcards. It's on amazon for $27.19

For ACT prep, highly recommended books include The Official ACT Prep Guide by ACT, which offers real exam questions, and Barron's ACT Prep for in-depth strategies and practice tests. Kaplan’s ACT Prep is also a solid choice for structured lessons and expert tips. Many students find combining multiple resources helps reinforce their learning effectively.

The actual official ACT prep guides are pretty thorough. I have a few editions from several years, and the best part is that they have tests in them. Most of the information doesn't really change, but the examples do change for each year's book. Honestly, if you're looking for something straightforward and relevant, just grab one of those, doesn't matter the edition, but if you want to hardcore study, I'd get the one from this year.