There are very large books put out by Kaplan, McGraw-Hill, and Princeton Review. Most libraries will have these books. If you can't find them through the catalog, ask a librarian. (Some libraries consider these reference material and will only let you take them out for very short periods, or only let you use them in the library). Most of the prep classes will use one of these books, so if you feel you can follow along in the book by yourself it's worth a shot.
If you are either young or low income, you might be able to find free prep classes locally. I would search for local Adult Ed (sometimes called ABE at community colleges), and maybe even make a few calls to the local school board and unemployment offices to see if they have any leads.
