Our Latin instructor has given us the list of Latin books for the fall and spring. They are all available Free at TextKit. We love Free!
These books will be used for a backbone to the courses and for exercises. In addition, they will make good reference tools. They are of course also available at Amazon, but Free makes .pdf very attractive.
Latin I: "Latin for Beginners" by D'ooge
Latin II: "Latin for Beginners" by D'ooge
Latin III: "Latin for Beginners" by D'ooge
"Latin Prose Composition" by North and Hillard
"A Latin Grammar" by Charles E. Bennet
Also, Cassel's Latin-English Dictionary is recommended for all 3 levels. However, it is not required if you already have a Latin-English dictionary. It isn't available as a free download. It's available in soft or hard cover (I've seen the hardcover at Amazon used for as little as $2.70).