Well it depends on the turbo tax product that you need. For simple tax returns you can use the free/free/free version. And it really is free. But depending on the complexity of your tax situation, you may not be able to use the free online version. It will work if you have just a W2 and that's it.
See the differences in the products on this link:
https://turbotax.intuit.com/personal-taxes/compare/online/The most popular is the deluxe (like if you have a mortgage, property tax, deductions). And if your tax situation is more complex you go up from there. I always get the top one (Premier Plus); and that is definitely not free but accomodates the complexities I need.