Piggly Wiggly - Wikipedia

On September 6, 1916, the first true supermarket, the "Piggly Wiggly" is opened by Clarence Saunders in Memphis, Tennessee. From the article:

"Piggly Wiggly was the first true self-service grocery store.[3] It was founded on September 6, 1916 (although it did not open until five days later due to delays in construction),[4] at 79 Jefferson Avenue in Memphis, Tennessee, by Clarence Saunders.[2] A replica of the original store has been constructed in the Memphis Pink Palace Museum and Planetarium, a mansion that Saunders built as his private residence, which was later sold to the city.

At the time of its founding, grocery stores did not allow their customers to gather their own goods. Instead, a customer would give a list of items to a clerk, who would then go through the store, gathering them. This created a greater cost, and therefore higher prices. Piggly Wiggly introduced the innovation of allowing customers to go through the store, gathering their own goods, thus cutting costs and lowering prices.[2] Losses due to easier shoplifting were more than offset by profits from increased impulse purchasing. Others were initially experimenting with this format as well, which initially came to be known as a "groceteria", reminding people of cafeterias, another relatively new, self-service idea.[5]

Piggly Wiggly Corporation secured the self-service format and issued franchises to hundreds of grocery retailers for the operation of its stores. The concept of the "self-serving store" was patented[6] by Saunders in 1917. Customers at Piggly Wiggly entered the store through a turnstile and walked through four aisles to view the store’s 605 items sold in packages and organized into departments. The customers selected merchandise as they continued through the maze to the cashier. Instantly, packaging and brand recognition became important to companies and consumers.[4]"