I do not think they're operating "at-cost" -- making a profit off of state taxes is a reasonable business model. I also doubt that California charges to e-file: https://www.ftb.ca.gov/file/ways-to-file/online/calfile/inde...

I'm really happy to use FreeTaxUsa and only pay $20 for my income tax though, because using TurboTax with contractor income it was $120 or more. I got multiple family members to switch to FreeTaxUsa.