I know several kids who never went to highschool. At 12-13 they enrolled in the local community college and got their GED at 16-17. It cost (at the time, in district) $2000 - $2500 per semester at the junior college. Although that's significant, the school district was actually paying ~$10,000 per student per year for public school so it was actually WAY cheaper.

Regardless, those kids who went straight to college from middle school seemed 10x better off and all of the ones I know (or am friends with) are doing great.