What to homeschool for free?? All you need is just a few supplies to go along with it, and internet access.
Check out Easy Peasy Homeschool. It has full lessons, for ALL grades, all subjects. Check it out at http://allinonehomeschool.com/.
Even if you already have your material, you can use this site for review. I love the math, as a lot of it is games--if kids are having fun, they will do it longer, and learn more.
Of course, you will still need to track your time, grades and such, and follow the state rules regarding your hours and core time. This site doesn't do any of that, it just provides the lessons. For free.