Belying its simplicity and ubiquity, the price tag is a surprisingly recent economic development, Aeon magazine writes. For centuries, haggling was the norm, ultimately developing into a system that required clerks and shopkeepers to train as negotiators. In the mid-19th century, however, Quakers in the US began to believe that charging people different amounts for the same item was immoral, so they started using price tags at their stores to counter the ills of haggling. And, as this short video from NPR’s Planet Money explains, by taking a moral stand, the Quakers inadvertently revealed an inefficiency in the old economic system and became improbable pricing pioneers, changing commerce and history with one simple innovation.

Most of us are used to prices that don’t change. You go into a store to buy some Quaker Oats, and they’re going to cost the same for you as they will for whoever tries to buy them next.

For most of human history, you had to haggle over prices before you could buy something.

The Quakers were among the first people to commit to fixed prices — and they did it because they thought it was more fair. Turned out, it was also good business. This is the strange story of the long journey of that little piece of paper.