It said $29.99 on the box, but when I brought it to the cash register it rang up as $19.99! I was so happy
I love that trick. It gets customers every time. They label all of the products at a higher price, but leave one marked at the lower price, which is the real price. Then when you find that one on the shelf with the lower price you go "Ooooh... I could rip them off a few dollars! Heh heh heh." And they go "Thank you for your business, sir.", wait for you to leave, and mark another copy at the lower price. Repeat.
It's simple, but it works.