Given the algorithmic pricing on a lot of things (everything?) sold on Amazon there’s probably money to be made building some bot that checks for pricing mistakes and buys when one is found.
I believe this was common on eBay. People also looked for common misspellings of items, misspellings that would lead items to get fewer ids and usually end underpriced relative to similar items.
I don't have this automated, but this is definitely still a thing, at least for used test equipment. I'm not clever enough to automate it fully, since often constructing the search terms is fairly difficult, but I definitely have scored some incredible deals ($40 for a perfectly fine HP spectrum analyzer a month ago). The only automation is some simple greasemonkey scripts, but there are definitely deals to be had on mis-categorized items. Likely this works best on specialized equipment that the average bulk auction buyer doesn't recognize, I would suspect that most industrial/scientific equipment would apply. This certainly won't apply to consumer items like a laptop though, the item has to be esoteric enough that a non-expert has difficulty even determining what it is.
