Meet the qualifications and it is free.
https://turbotax.intuit.com/modals/simple-tax-return/
if you do not try elsewhere
https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free
If you do
Of course, make sure you qualify for the free edition.
https://turbotax.intuit.com/personal-taxes/online/file-your-own-taxes/ Scroll down and click 'See If I Qualify.'
My son had the same problem. Never figured out exactly what the problem was but I took a few extra steps and went through it myself and got it to come out correctly.
1st thing I did was delete all the forms to start over. Not very straightforward but was finally able to do it using the menu on the left and selecting something like tax forms and working through those menu items. Perhaps doing what ee-ea suggested to reset would be easier.
2nd thing was a started with a different browser and cleared the cache and stared over and went through the motions. Also, twice it presented me with a table showing Free Edition and also some upgrade options. This was confusing because the 'Free Edition' column 'clickable' selection at the bottom said "Not Now" and then there were two other options with charges. I'm wondering if my son had clicked something other than 'Not Now'. It made zero sense to me, because it seemed as though you were saying 'Not Now' to the Free Edition, but I clicked 'Not Now' and kept going. This time in came out with the free edition zero charge vs displaying Deluxe and showing a charge.