If I start out filing on the free TurboTax version, and decide to use a different service, will there be a fee for an incomplete filing through turbotax?

No there is no fee if you do not file with TT using the Free Edition.   You can clear out your data, or simply abandon the account.

 

If you have not registered, paid or e-filed you can clear and start over 

CLEAR AND START OVER

 

https://ttlc.intuit.com/turbotax-support/en-us/help-article/change-service-level/clear-start-turbotax-online/L37BZFuBV_US_en_US?uid=m6b26ost

 

No, there are no fees when using the TurboTax online editions unless the tax return is either e-filed or printed.

Ok, thanks