... I can't charge anything for that simple of a return.
Also, I find this statement highly questionable. While there're certainly more complicated returns that VITA can't do, as long as the individual is low enough income, VITA can and does do returns with the following:
Form 1040EZ, 1040A, 1040
Schedules A, B, D, C-EZ, EIC, R, SE
Form 1040 – V
Form 1040 – SE
Form 2441 (child and dependent care credit)
Form 8863 (education credits)
Form 8880 (credit for qualified retirement savings contributions)
Form 8812 (additional child tax credit)
Form 8888 (allocation of refund)
Form 8917
I find it highly unlikely that you'd do the taxes for someone with all (or several) of the above and not charge for it. If it's true, you are truly unusual, considering that the average preparer charges over $250 for just a 1040 with a Schedule A and state taxes.
"Recently, the National Society of Accountants (NSA) conducted a survey which showed that the average cost of professional tax preparation is $261. This is price that most tax preparers will charge for a 1040 Tax Form with itemized deductions (Schedule A) plus a state tax return."
http://www.irs.com/articles/tax-preparation-costs-and-fees