There was a time when shopping at a dollar store had to be a cloak-and-dagger operation; duck in, duck out, no eye contact, and not a word about it to anyone. It wasn't just highbrow nonsense, either.

On June 1, 1955, in Springfield, Ky., J.L. Turner and his son Cal Turner came up with a simple concept for a retail store: No item could cost more than $1. Their store, Dollar General, spread to other ...