What is "trading stamp"

n. a small paper coupon, given by a retailer to a customer; they may be saved up and redeemed for goods

n. a stamp given by a retailer to a buyer; redeemable for articles on a premium list

Trading stamps are small paper coupons given to customers by merchants in loyalty marketing programs that predate the modern loyalty card. Like the similarly-issued retailer coupons, these stamps only had a minimal cash value of a few mils (thousandths of a dollar) individually, but when a customer accumulated a number of them, they could be exchanged with the trading stamp company (usually a third-party issuer of the stamps) for premiums, such as toys, personal items, housewares, furniture and appliances.