In June of last year my brother and I walked into a Fry's electronics store in Concord, CA to buy a couple of video cards. I noticed they had geforce 9800gtx+ for $99. We each picked one up, went to the check stand thinking nothing was wrong. The lady at the checkout scanned mine, looked at me, then told me she would be right back. When she returned she had a completely different card, same model, just made by someone else and told me it would be $216.48. I quickly knew something was up, and they had pulled a switch.
Long story short, they tried to tell me they didn't have those cards advertised at $99, those were $199 cards. Luckily for me, my brother still had his.. They "found" my card and sold it to me for $99. In the end, they lost a customer.
Companies need to honor price mistakes, even if it costs them allot.