Filing with the 'Free Edition' of Turbo Tax is reserved for basic tax returns that have the following stipulations:
•Made less than $100,000
•Don't own a home or rental property
•Didn't sell investments
•Don't own a business or have 1099-MISC income
•Don't have any major medical expenses
Every other version has its respective benefit and fee. Please see the link below that compares all versions and will help you to select the best one for your tax situation.
https://turbotax.intuit.com/personal-taxes/online/
Free Edition is for simple filers that file a 1040EZ (or a 1040A with a standard deduction), and is free as long as you don't select any add-ons or upgrades.
https://turbotax.intuit.com/personal-taxes/online/free-edition.jsp
Form 1040EZ and Form 1040A are the only federal tax returns that are supported using the Free edition; therefore if you need to enter tax data that cannot be entered on these 2 forms then you will be prompted and required to upgrade to a suitable version.