The ability to quickly check whether one is infected with COVID-19 is about to get easier and less expensive, with Amazon, Kroger and Walmart each set to offer within days at-home, rapid tests — with no retailer price markups, according to the Biden administration. "Americans will be able to buy these tests at their local retailers or online for up to 35% less starting by the end of this week" and continuing for the next three months, the White House stated Thursday.