I also have a couple distinct memories of getting served ads for products I've never searched for or never bought before, after I either bought it in a store or, even weirder, literally just picked it up, looked at it, and put it back on the shelf in a store?
I can craft some kind of super-surveillance-state theory as to how you could achieve that, but it feels very unlikely to be deployed at a small CVS lol
Anyways, these might just be coincidences but still perplexing to understand how it's done.