In the sales tax section, choose Easy Guide and tell the software about the car purchase on the page Enter Major Purchases. Here's how you can navigate to the sales tax entry in TurboTax Online: Navigate to Federal > Deductions & Credits > Estimates and Other Taxes Paid > Sales Tax > Start or Revisit If you're itemizing, you must choose between deducting your state and local income taxes or your state and local sales taxes. You can't claim both.