Many places offer ESL classes that teach people English as a second language, and there's lots of ways to find reasonably priced classes, even free ones.

Some high schools and colleges will offer English as a second language classes for free to people that live in the community. They're often times free due to the fact the teachers will be volunteers or people working on a degree. Sometimes they aren't free, but usually they only ask you to pay a small fee for a spot in the class.

Look in community bulletins, sometimes churches and local organizations will offer English as a second language courses.

If you don't care about the social interaction aspect, there are lots of websites online that offer English lessons. Many are free, though some will charge a one time fee for website access.

Rather than using the internet, you could also self teach with either books or DVD's. Under Resources I have listed a few popular ESL books and movies that have proven to be successful.