If you filed a state return, then TurboTax charges for Federal return preparation, whether filed or not. You cannot prepare just a state return. The state return relies on information from the Federal return. You have to prepare a Federal return first so that you can prepare the state return. You don't have to file it, if you don't need to, but you are charged for it. In fact, it won't let you print the state return to file until you pay for both the Federal and state returns.
If using Online Deluxe, a Federal return is 59.99, and a state return is 44.99.