Over the last decade, the average tuition and fees at private four-year schools rose 26 percent. It's even worse at four-year public schools, where it has jumped 35 percent during that period. Yet for many prospective students, free college is becoming a reality, as more states adopt scholarship programs to increase enrollment and accessibility.

These so-called promise programs typically offer college students two years of free tuition at participating state community colleges or other associate-degree programs and vocational schools. Most are what's known as "last dollar" scholarships, meaning the program pays for whatever tuition is left after financial aid and grants.

Eleven states — Oregon, Nevada, Arkansas, New Jersey, Maryland, Tennessee, New York, Rhode Island, Delaware, Kentucky, and Indiana — already have these programs in place and nine more are working on legislation to do so.