Vaccines and even monoclonal antibodies are free (though treatment may cost money still: the price of the hospital beds and whatnot).

The $31 joke is about IVM: lice / parasite remover that people are taking because they think it cures COVID19. At least, that was my interpretation of the joke.

Well not quite. My parents are convinced this whole vaccine thing is a worldwide conspiracy invented and managed by big pharma to which deep state and big tech are subservient. Breaking down the numbers to show how ridiculous that idea is, somehow still didn't help.