If you are receiving something of value -- your sons' tuition -- in return for your work, you are being paid, and that is income under the law.  The school is right.However, one way to make this work at least a little more easily would be if the school were willing to give you an employee discount on the tuition, and you in turn worked for less than the market rate for whatever work you did there, as long as the minimum wage law was not being broken.  Of course, the school would have to agree with this, and you would have to do enough work to cover the tuition and all your taxes on the earnings.  If this is an option, a CPA could figure out the numbers for you.