If you're looking to save your money, I'd recommend using a combination of translations freely available online. Caesar's "De Bello Gallico" is a very common beginner's Latin text.
Perseus has the Latin text as well as an English translation (listed under "Editions and translations"). Plus, the dictionary tools should be of great use to you.
http://www.perseus.tufts.edu/cgi-bin/pt ... 99.02.0002
If you tire of Caesar, just searching around online should turn up plenty of translations of the most popular Latin works.