Unbelievable CVS story

So I went to CVS because I had a coupon for a free hand sanitizer spray pen. I looked around the store and found nothing else that I needed or wanted. Took the coupon and the pen to the register and the gal scanned my card, my bag card and the pen .... then she says do you want some gum or something? I said not really. She states that my total was -$0.40 ... so I got a dove candy bar that was on sale for $0.50 and only paid $0.11. CRAZY!!!