If you live in the United States you will find free English resources in libraries and publicly funded continuing education programs. Free classes are often sponsored by non-profit community organizations that use public funding. Library classes are usually conversational or computer based labs. Non-profits are sometimes funded to teach English to immigrant job seekers or refugees settling in the country.
No matter what level of English you are trying to master, go to places where English is spoken. Limited English speakers may feel reluctant to mingle with English speakers, but taking part in activities is an effective way to learn. If you live in an English-speaking country join sports teams, attend religious services, eat at restaurants and volunteer for civic groups. If you live where English is not commonly spoken, join an English club.
A quick Internet search will turn up dozens of sites that have interactive or down-loadable English practice materials. Many of these sites want to sell you something, but also offer lots of free lessons, games and audio samples. Other sites are completely free. Don't overlook the value of simply watching English television or listening to the radio. These resources are a big help in the day-to-day English practice.
English students often do well having someone to practice with. Look in the local classifieds to find English study groups, or start one yourself. You can often find these groups on social networking sites, like facebook or craigslist. If you'd like to get a tutor, offer instruction in your native tongue as barter.