According to market researchers TNS, 85% of UK households have a loyalty card.
(Loyalty cards are issued by supermarkets and department stores, they entitle you to freebies or cash simply for shopping. Of course, retailers get something in return: they record information about what you buy and build up a profile about you. And the most annoying thing of all is that every time you go to pay you will be asked "Have you got a ..... card?")