An art collector is walking through London looking for a Christmas present, when he notices a mangy cat lapping milk from a saucer in the doorway of a shop.
He does a double take, when he notices that the saucer is extremely old and very valuable, so he walks casually into the store and offers to buy the cat for two pounds.
The shop owner replies,
“I’m sorry, but the cat isn’t for sale. ”
The collector says, “Please, I need a hungry cat around the house to catch mice. I’ll pay you twenty pounds for it. ”
And the owner says, “Sold, ” and hands over the cat.
The collector continues, “For twenty quid, I wonder if you could throw in that old saucer. The cat’s used to it and it’ll save me having to get a dish.”
And the owner says, “Sorry, but that’s my lucky saucer. So far this week I’ve sold sixty-eight cats. ”