Use Google Translate or Yahoo Babelfish to get a rough, literal translation from Spanish to English. Although these translation services do not provide a very detailed analysis and miss the nuances of language, they are a good place to start if you want a quick and free translation of any text into English.
Check Craigslist for local translators, specifically Spanish-language students, who might be willing to do translation work for reduced prices to add to their experience. To find translators, go to the Craigslist city listing, pick the metropolitan area closest to you, and under "Services", choose "wrt/ed/tr8."
Look into translation companies offering low-cost translation services. "Absolute Translations" offers pricing quotes if you can provide the word count and document type. This company uses teams of live translators for their services, which can result in more accurate and nuanced translations. Kwintessential offers "low-cost" translating services by translators "in-training." The website emphasizes that this service should be used only for documents where specific and nuanced translation is not necessary. Kwintessential also has a higher-cost translating service that uses more experienced translators and charges a higher fee.