That depends on which version you are using. The price of state when using TurboTax Free Edition online varies from the state price when using Deluxe Online or higher version. You can go here https://turbotax.intuit.com/personal-taxes/online/ and click State additional under each one and a pop-up will appear with state cost.
And if you are using TurboTax CD/Download versions, you can go here https://turbotax.intuit.com/personal-taxes/cd-download/ and click either State additional or 1 state download to see cost for each additional state.
