In order to enter investment sales from a 1099-B you have to either upgrade to TurboTax Premier Online or use any edition of the CD/Download TurboTax software. You cannot enter your 1099-B in Free Edition.
You might qualify to use IRS Free File Program delivered by TurboTax. It's at the following link, and the qualifications are listed there.
IRS Free File Program delivered by TurboTax
