If I remember correctly, you have to go through the IRS freefile page (here: https://apps.irs.gov/app/freeFile/) to get to the "real" free version of turbotax. The link to the "free edition" on the main page of their site, confusingly, is something else.
Turbotax's income limit for free filing is really low, though. Max income of $36,000.
I make more than that and didn't have to pay to file electronically. I downloaded turbotax through the iOS app store, using the app store search. Is this specifically for 1099 workers or something? (I get a W-2)
Edit, did some searching and it's completely free if you're able to file via a 1040EZ, which I'm pretty sure was my method. I don't know too much about tax filing though, so maybe I'm confused about things (I mean, I'm definitely confused about tax things overall, haha). I'm 100% positive TurboTax didn't take any additional money from my refund though.