I worked in groceries story when I was younger.

But funily enough, it's probably one of the rare times I'd have answered "yes"!

We got a policy here where anything mislabelled under 10$ is free for the first item. Anything over 10$ gets a 10$ rebate.

My understanding is that it was put in place a while ago when stores stopped labelling individual items to keep them in check and ensure that consumers had a recourse in case of mistake.

Source: https://www.opc.gouv.qc.ca/en/consumer/topic/price-discount/store/tip-sheet/

NULL being "no money" by any definition, and the regular price for this probably being under 10$... well, it's probably free!