They were intended to be placed into booklets, and when the booklets were filled up, they could be redeemed for various "gifts." These were things like inexpensive appliances, towels, and other household goods.
They were used by merchants to attract repeat customers to their stores.
You may also have had the variant of "dividend" stamps, used by the Co-op stores in the UK. Stamps in a booklet, and then, I think, a money payment. The current shop loyalty card is, I suppose, the modern version of these things.
As Mr. Drummond indicated, what you have is commonly known as "trading stamps". Similar to S&H "green stamps", Jewel T premiums, coupons found inside cigarette packets, etc. IOW, an early form of "affinity marketing".
Believe Wallace & Co was an early purveyor of affinity/premium marketing programs for retail companies within the U.S. Believe the stamps you posted were employed by Piggly Wiggly markets. A grocery chain found in the US southeast.