Public Education (College) Tuition could easily be made free. Current merit restrictions by University would still be in place, so students would still have to perform just as well in high school and continue to perform well in college to get in and stay in. Thinkprogress.org and Theatlantic.com are sources that come to the conclusion of the cost being about $65b annually - only 1.9% of the 2013 Federal Budget and under that percentage for the current Federal Budget.
Making tuition free would solve many problems of under education, eliminate excuses to be lazy and uneducated, eliminate horrendous student debt traps, and increase the USA's standing in terms of how educated the people are.
All in all this should be done - considering we spend over 3.5 trillion annually.