If the goal of education is to produce 18 year olds with social adjustment, like and work skills, and the ability to work or get into college, let's be explicit about that! If there's a clear goal, a market, and competition, costs always go down.
Web browsers are free because both companies and non-profits can build them, benefit from providing them, and can't charge more than free. Computing used to be done by hand by humans, now you can buy millions of person-equivalents of computing for less than the cost of coffee. Why is it so cheap? Because companies wanted the dollars people would give in exchange for fast computation. Horses aren't used as transportation because someone invented cars, people fly across the ocean instead of taking ocean liners, etc because companies wanted the money people would spend on fast travel. Pens exist because companies wanted the dollars people would spend on fast, clean writing. Look at anything around you and it's there because someone outperformed other people in the competition for the dollars you spent on it. Every time, you either got the same product for less money (think Dell laptops), a better product for the same money (think of how Apple provides the best product they can at basically fixed price points), or often a better product for less money.
Schools districts spend between $5-15K/student/yr. We're doing it the same way we have for 100 years. Lack of competition or even an opt-out policy has given us a worse product for a higher cost (http://reason.com/archives/2010/09/16/money-is-not-what-scho...). It is very, very, very reasonable to expect that open competition with well-defined expectations would be both cheaper and better.