Have you researched having your taxes done by a VITA volunteer? I think VITA stands for Volunteer Income Tax Assistance. Volunteers go through IRS-approved training to help low-income people file their taxes. I think the income cap was $49K per year.
We've had our taxes done by our local military VITA office for several years now. They don't charge us for their service, and we've been very satisfied with the results.
I can't seem to find a centralized website for VITA, but check your local yellow pages or call 411 if you think you might be interested.