On of your basic rules of retail is that if a customer starts shoving piles of cash at you, take it.
Yet this seems to have escaped the checkout crew at the Boise, Idaho, CompUSA, who went into a panic when a customer started counting out Benjamins for a 10-percent-off iMac. The hapless bargain hunter was told with some alarm: "Sir, we don't accept cash for this kind of purchase! You must use a credit card!"
And there's another clue for anyone still wondering how CompUSA managed to drive itself into oblivion.
CompUSA Refuses To Accept Cash [Consumerist]