I have both federal and state info in turbo tax but I only want to file state and see if I qualify for a free filing

If the federal tax return is not e-filed then the state tax return cannot be e-filed, it would have to be printed and mailed to the state.

Can you file just the state return?

Can I prepare and file just my state return using TurboTax?

You have to first fill out federal for it to flow to state and pay the fees for both by credit card.  And you will have to print and mail state.  You can only efile state if the federal was efiled and accepted from the same account.