The regular TurboTax Free Edition is not available to everyone. You apparently have a tax situation that normally requires paid TurboTax, usually because the return requires an additional form besides the 1040.
There are some alternatives to paying for TurboTax. If your AGI is less than $39,000 ($72,000 if active duty military) or you qualify for EITC, you can switch to IRS Free File TurboTax thru freefile.intuit.com. (Turbo Card & Refund Advance are not available there.) If your AGI is between $39,000 & $72,000 and you don't qualify for IRS Free File TurboTax, you can go to irs.gov/freefile and select another provider to do your taxes for free.