They are readily available now. The sell for $7 and up. Finding one during big surges like this past January, though, is a different matter.
Studies show they are pretty accurate, but I know many people who got false positives. Maybe user error.
We get as many as we can and stockpile them within reason. 4 free from the Government for the 3rd time now, we also get 8 free per month from my insurance company upon request. We've used 7 so far (precautionary testing, all negative so far) and have 29 stocked up for when we need them or family/friends need them. All of those were of no cost to us.
ADDED CORRECTION: The US government provides 8 per address, not 4 as I incorrectly stated. They just opened up the 3rd round. We submitted our order immediately.