Interesting article from Chris Palmer about a trip to Abercrombie & Fitch. One thing I like about Massachusetts is their very strict pricing law which pretty much requires everything to have an individual pricetag (or meet some onerous consumer-friendly conditions). I encountered a discrepancy at a high-end liquor store in Waltham. An expensive single estate cognac was about half the price it should be. I brought it to the front and the scan didn't match the price. The cashier happened to be the owner. We ended up agreeing to sell the bottle at his wholesale price (the law does give leeway for "gross" errors). I'm sure he then ran off to fix the problem.
When I was in high school, I'd drop by Office Depot. They consistently mispriced pens. Buy pens, pricecheck them, get them free. It was a routine thing for a several month period.