I've have a similar problem that I fortunately caught - and more than once, I might add, at two different box stores. You pick up some items that have big sale signs posted on the shelves; then when they are scanned, they are rung up at the normal prices. I haven't known if these situations were contrived to deceive, or if it was just that the scanner programmers weren't keeping up with the floor staff, but I am glad I always watch my checkout, and catch these things. My hubby thinks I'm a little paranoid, but hey - someone's gotta look out for #1!