IN their race for the consumer’s dollar, U.S. retailers have turned the old trading-stamp gimmick into the hottest sales idea of the postwar decade. By playing on the housewife’s weakness for ...

Early in the year, the Trading Stamp Institute had predicted a 5% to 7% increase in stamp sales for 1966. But Sperry & Hutchinson Co., whose Green Stamps account for about 40% of the industry’s ...