If you don't qualify for the TurboTax Free Edition, you may qualify for the IRS Free File Program delivered by TurboTax . It's geared towards lower-income filers, regardless of tax return complexity, and is only offered through the IRS Free File Alliance (FFA) program. No upgrades are available.
To see if you qualify, click on What is the IRS Free File Program delivered by TurboTax?
If you qualify, see How do I switch to IRS Free File Program delivered by TurboTax?
Source: TurboTax FAQ