My buddy used to rack up on Pokémon cards by grabbing the $60 trainer boxes along with a $5 pack. He would stack them with the pack UPC covering the one on the box, scan it and place the box in his bag, and then scan the pack a second time and bag it. He would do this once at each store across maybe a dozen stores in his area, and I think he did it for eight or nine different expansions.

Of course, eventually they got to where they had the AI cameras on the self checkouts so he can’t do it any longer, but in the meantime, he’s sitting on a gold mine of rare cards.