https://www.covid.gov/tests four more free tests being handed out by the government. Once you have them, you can reference the FDA's site here to figure out how to properly conduct serial testing with them. The reason being is that as more and more variants have emerged, false negatives on rapid antigen tests are much more common, especially when asymptomatic. However, a positive test is still a clear indicator that you currently have covid and are transmissible. This website can also be used to reference tests you already have that have a printed expiration date that may be inaccurate - these were rolled out with such expedience that the printed dates were more estimates than hard and fast cutoff dates, and so some of them have had those dates updated as they remain effective past the printed date on the box.
Also, there's boosters available again! Pfizer and Moderna have another mrna-based booster that's targeting one of the many variants currently jockeying for dominance, but testing indicates it performs adequately against others. For those who would prefer a more traditional vaccine, Novavax has a new booster that is waiting approval, but Pfizer and Moderna like being the only names in town it's unclear why it hasn't been pushed through yet. The rollout has lead to some areas getting resources sooner than others - you can schedule appointments at your local CVS or Walgreens for one right now but don't be surprised if they cancel it and tell you they don't actually have the new shots yet. Insured folks are supposed to be fully covered for the cost of the shot (although your given insurer may be slow to update policy or picky about where you get it because we live in hell!), uninsured folks can rely on the CDC to find a free shot, or be prepared to spend anywhere from $120-$200 for a jab, factoring in the base cost of the vax and arbitrary service charges/markup from a given provider.
I did my best to avoid editorializing here and I hope this information is helpful to someone. If it's not, sorry. If you don't like seeing covid stuff, sorry.