From the USA.gov Blog:
Do you need help preparing your tax return? Learn about the IRS Volunteer Income Tax Assistance (VITA) and Tax Counseling for the Elderly (TCE) programs.
VITA Program: If you make $51,000 or less, IRS-certified volunteers can inform you about tax credits for which you may qualify and prepare a basic tax return with electronic filing.
TCE Program: If you are 60 years of age or older, you may qualify for free tax help from IRS-certified volunteers who specialize in issues that pertain to seniors.
There are thousands of locations across the United States where you can get free tax help through the VITA and TCE programs.