What are the average annual per-student costs to taxpayers for public education (K-12)?

Answer 1

Each state has a different cost.....below are some links that might help.
http://www.speakout.com/activism/education/
http://www.issues2000.org/Background_Education.htm
Teacher Pay: K-12 Teachers’ salaries average $34,200; college instructors average $63,000; compared to $50,700 for similarly educated non-teachers. Public school teachers earn 25% to 100% more than private school teachers. Generally, any reference to ‘increasing teacher pay’ implies opposition to vouchers while negative references to teacher’s unions implies support of vouchers.

Answer 2

Well I think your main point here is that 1 in 3 actually graduate, so why waste 120k. I would say the reason that 1 in 3 don't graduate is because they have teachers that don't care about a child's future, and are just there from 8-3 everyday to get paid and go home.