A deal that Walmart and Kroger had previously made with the White House to sell Abbott’s COVID-19 at-home test kits at cost expired in December; now, the retailers are hiking the price.

As of Tuesday the BinaxNOW kit, one of the first at-home tests to be authorized by the federal government, was listed on Walmart’s website for $19.88 while Kroger had the test listed for $23.99. The kits had both previously been about $8 cheaper, according to reports.

The agreement with Walmart, Amazon and Kroger was announced by President Joe Biden in September.

A spokeswoman for Walmart said Tuesday that unlike other stores, the retail giant continued selling the product at cost through the holidays, NBC News reported.

“We have seen significant demand for at-home COVID-19 testing kits and are working closely with our suppliers to meet this demand and get the needed product to our customers,” she said, according to the news outlet.

In a statement to CBS MoneyWatch, Kroger said it had fulfilled its commitment to the Biden administration and that the “pricing program has now been phased out and retail pricing has been reinstated.”

Amazon has not responded to a request for comment and as of Tuesday, the tests were not available on its website, according to NBC.

Last month, Biden announced that the administration “plans to ship as many as 500 million free test kits to people who request them through a website — a plan experts have said will require significant scaling up,” NBC reported. The first batch is expected to ship sometime this month.