I had a coupon for a "sewing notion" at Joann. I picked up an Omnigrid template and was told, that was a quilting notion - not eligible for the coupon. I was directed to a wall on the far side of the store. Found an almost identical Omnigrip template, $1 more. Somehow THAT was not eligible either, despite coming from the "notion" wall.
The cashier was very nice and worked with me to override it and get down to almost the coupon value.