There are two primary types of collegiate institutions in the United States: private colleges and state colleges and universities. Private college tuition averages $26,273 per year while state schools average $7,020, as of 2009. Of the top three colleges known for their physics programs as listed in "U.S. News and World Report," tuitions range from $18,949 at Elon University to $32,649 at Carleton College. These figures do not factor in scholarships and financial aid.
In some states, high school students may be able to take some college physics classes for free or at a reduced rate, and the class credits may apply both to their high school graduation and to their college degree. This can significantly decrease the amount of time it takes to get a degree, and cause the cost of college to decrease significantly. Most dual programs allow you to take general education requirement classes which are the bare bones of a college education, but since science courses are usually part of a college's core curriculum, physics classes are likely to be available.
Another way to decrease the cost of a college physics degree is to attend a junior or community college for a year or two and then transfer to a senior college or university. This allows you to get your general education requirements out of the way without paying the higher costs of a four-year institution. Then if you keep your grades up, you can transfer to a university with a good physics department.
Similar to the junior/community college transfer, you can attend a state college for a couple of years and then transfer to a private college's physics program. This way, your first two year's tuition will be at the state rate and the last two years at the private college rate.
Through scholarships and grants, most students are eligible for some form of financial aid. There is a form called the FAFSA, the free application for federal student aid. If you fill out one of these forms and submit it to your college's financial aid office, it can drastically affect the cost of a college education by qualifying you for various grants and scholarships, including scholarships specifically for physics majors. The FAFSA must be filled out every year.