Residential households in the United States may order one set of four free at-home COVID-19 test kits from the United States Postal Service.

The rules limit one order per residential address but each order will contain four individual rapid antigen COVID-19 tests. Orders will ship free starting in late January. Order forms may be found at http://www.special. usps.com/testkits.

It is estimated the free tests will cost the federal government about $4 billion.