According to student support organization College Board, published tuition fees for 2014/15 at state colleges are an average of US$9,139 for state residents, and $22,958 for everyone else. This compares to an average of $31,231 at private non-profit colleges. The cheapest options of all, however, are public-sector two-year colleges- also known as community, technical or city colleges- where average fees for 2014/15 are just $3,347.
Admittedly, you can't complete a full degree at a two-year college, but you can gain an associate's degree. This counts as the first half of a bachelor's degree, which can then be completed by transferring to a university for an additional two or three years.
Average fees at US universities, 2014/15