By DARLENE SUPERVILLE
WASHINGTON (AP) — President Joe Biden says the federal government will buy half a billion COVID-19 rapid test kits and distribute them free of charge to people to use at home. But it will be a few more weeks before any tests go into the mail. That’s primarily because delivery of the first batch of the 500 million tests isn’t expected until early January. The administration also is still finalizing details for how the ambitious program will work.