$0 Is The Cost Of Making Public Colleges Tuition Free
This video by Slate looks at the federal government funding for education in the context of purely how much money goes into the college education system (e.g. through pell grants.)
It concludes that the amount that the government already spends on higher education, around $70 billion dollars, "more than enough to cover the cost of every student at each and every public institution the country."
The video goes on to look at some of the criticisms of making college education free - for example, it would be funding school for students from high-income families who could afford to pay for college. It even goes on to propose a hybrid system where those students would pay a reasonable amount while lower-income students would pay nothing.
Ultimately, it challenges the notion that it would cost too much to make college free for all students.