After "review", purchase TurboTax product, and before "file", can I still edit my tax return?
Yes you can just click on the tabs at the top to go back to the section you need to edit. (Personal Info, Federal Taxes, State Taxes, Review, File Are the tabs you can choose.)
You have clicked a link to a site outside of the TurboTax Community. By clicking "Continue", you will leave the Community and be taken to that site instead.