The reason you can't efile is because a tax return with 0 income was already efiled for you when you used the non filers portal. The charge from TurboTax is for preparing a tax return with a 1098-T. That form cannot be filed using the Free Edition. You will have to print and mail your return to get it accepted. The normal process would be to complete a 1040X amended return but some are suggesting that you can just prepare and print your "real" original return and write "Amended Return" across the top of it and mail it.
There is another free product called the Free File Program that you might be able to use to prepare your 2019 return for no fee. https://ttlc.intuit.com/questions/2026912-how-do-i-switch-to-turbotax-free-file-program
You qualify if you had $36,000 or less AGI or $69,000 or less military family AGI or qualify for EITC. Click on See if you qualify then Yes (if you do) then Start Now button, then choose Create an Account.
To prepare and file a 2018 tax return, you must buy and download the 2018 product and install it on your computer: https://turbotax.intuit.com/personal-taxes/past-years-products/
A 2018 return can no longer be efiled. It must be printed and mailed. Mail each tax year separately.
