If you are using TT online, it is "free to start". If you start in the basic version, you will be prompted to upgrade if you enter a situation that requires an upgrade. If you only upgrade to itemize, and then the program says "you don't have enough to itemize and standard is better", then you can downgrade back to the free version by choosing the "Clear and start over" option and entering your data again. However, there are other reasons you might have to upgrade and if you have one of those situations, itemizing or standard will not make a difference.
If you are using Turbotax installed on your own PC or Mac from a CD or download, there is no "free" version. There is Basic and Deluxe, but Basic does not include any state income taxes. If you live in a state with income tax, the most cost-effective option is to buy the "Deluxe Federal+1 free state" CD from a reputable retailer like Staples, Target, or Amazon.
