Costs less.

Your parents would be arrested for failing to responsibly send you to school. But the sad fact is that Khan Academy and PatrickJMT will teach you more than your teachers will, and that high performing public schools are only for rich families that pay very high property taxes.

Before you have to join the real world, learn as much as you can. Tutorials and books can subsidize your education, but it also arms you with questions you can ask your teachers. The right questions.