What would you have done if this had happened to you?

Monday I purchased an item at Menards...the price was $49.99. When I checked out, the cashier charged me $4.99. Wow....I said to her "that's quite a bargain", she just smiled and nodded. My husband was waiting for me, I told him about the lower price, we checked the item against the receipt and noticed that the cashier had punched in the wrong number. I then went back, told her what had happened, and she sent me to Customer Service. The problem was corrected and I paid the correct price. They were surprised that I had caught the error and paid the full price, saying most people would have just ran out the door.