I haunt thrift stores, and almost always there are SAT/ACT prep books for sale for a couple dollars. You can probably get them for free from your local library.

In my not-so-humble opinion, however, the best way to prep for the verbal SAT is to read books. Novels are fine.

For the math, prep by taking all the math classes your school offers, and make an effort to learn all the material.

Do that, and you won't need prep classes, and you'll also be well prepared for college.