This is 100% free and so is shipping through the USPS.

This is the article from the FTC on this (and also some tips to avoid possible scams) and the link inside to begin the order …ftc.gov/…/how-order-free-covid-test-kits-federal…

They limit 4 per household and do keep in mind that these tests do expire, but it seems wise for everyone to still have some on hand if someone believes they have symptoms. If nothing else, you’ll have some to share with friends if the expiration is close so they don’t go to waste.