A lateral flow test or something using a lab?
Must be a lab test as lateral flow is like ยฃ2:
https://www.boots.com/flowflex-antigen-rapid-test-lateral-flow-self-testing-kit-1-test-10312288
Or $7 in Walmart: https://www.walmart.com/ip/Flowflex-Covid-19-Antigen-Home-Test-1-Test/837992467?classType=VARIANT&athbdg=L1200