For years now the USPS has had a congressional mandate to be self-funding. Yes, the prices of some services have increased a bit, but then the prices of all private goods have increased as well. The service has remained excellent.
Some places work better than others, but all places get reliable and consistent service.
I was thinking that the education system could benefit from such a move. Take the money we spend on education, and return it to the tax payers. Then let the schools fend for themselves. They would charge tuition just like the USPS makes you buy stamps. Obviously, unlike the USPS, this system would need to be tailored to the education systems specific needs.