I hope it's OK to give a non-sarcastic, useful response to a valid question. Are Wrong Planet posters in an especially septic mood today? I assume the question was asked in good faith; it's flip responses like the ones I waded through to get here that turn me off of forums, and I think my days on this one are numbered.
Now: The suggestion to go to the library is a good one. Our local public library allows renewing books for up to six months (!) (I know, because I've done it--after six months they wanted the books back, though...). Other materials can be renewed for varying periods. In that time a person could get a general idea of whether they wanted to pursue the language in question or not--at least. At best, you could actually learn the basics of the language without renewing many times.
But you could learn a language with your own materials for very little money by visiting a store such as Half Price Books, where there will be a large selection of language courses available--sold by people who either learned the language and didn't need the CD's and books anymore, or, more likely, gave up.
And last but I think most important, there are numerous web sites offering excellent foreign language instruction for free. It's hard to believe, but true. A Google search will be profitable here. At least one site offers interactive study with native speakers--and all for free.
I keep up my French and Spanish to a certain extent by subscribing to Web comics in Spanish and reading French news articles on the Web.
Good luck.