It sounds like you are using the desktop software installed on your own computer. In that case, there is indeed a separate e-filing fee for each state tax return, even though there are no additional fees for filing more than one federal tax return.
There are three ways I can think of off the top of my head to avoid paying the state e-filing fee for your sons tax return. 1), print and mail it. 2), tell TurboTax that you will print and mail his state tax return so that you have a copy. Then, go to the your states tax website and look to see if they have a free e-filing system. Their e-filing system may not perform complex calculations or have an interview, but they may have a place where you can copy the numbers from his printed tax return into an online form which you submit online with the state for free. Or 3, You could do as user SweetiJean suggested and create an online account for your son’s return. TurboTax online is free if it is a simple return with no additional attachments like schedule one or schedule three for student loans or college tuition. Or, the IRS free file version of TurboTax is free for any taxpayer with income under $36,000 even if they have additional forms in their file.
