This may not hold true in the US, but in Alberta (I don't know the exact figures anymore, but the ones I'll use aren't off by much).

Each child gets a basic grant from the department of education. It goes to the school division. It is about $4500 per child (if there are no special needs difficulties--more if there are). However, a 'certified teacher' is required by law to 'run' each child's program. If a parent decides to home school, the parent will receive half ($2250) and the school will receive $2250 with the stipulation that the school ensure the curriculum is being followed, etc. MANY school divisions do not do an adequate job of that, and some parents (I'm thinking religious home ed. here as one example) buy courses--or not--and 'educate' their children. I know the system has been played around with on more than a single occasion although I won't go into details on this thread. (I'd be happy to message you about the examples I know of.) Lotsa room for improvement anyway.

That said, I know of home-schooled students who have been exemplary and gone on to be very successful in college, trades or university.