Free high school education for everyone

I would like to see all on- line high school classes offered free to anyone that wishes to complete high school .
 Classes are  currently only free to students under 21 years of age and if your an older adult student you must pay anywhere from $50.00 to $200.00 per credit to complete missing high school courses to get a diploma.
If these courses were free to adult students, I think a lot more people would finish high school.