If others are confused this link spells it out:
https://aspr.hhs.gov/covid-19/test/Pages/default.aspx
Coming soon! Order your free COVID-19 Tests at the end of September.
U.S. households will be eligible to order 4 free COVID-19 tests at COVIDTests.gov. The COVID-19 Tests will detect current COVID-19 variants and can be used through the end of the year.
Bolding added mine