Who was the inventor of fixed prices in department stores?

Henry Ford was not the first with fixed prices... In the middle of the 19th century, such drg goods merchants as A, T, Stewart in New York and Marshall Field in Chicago attracted customers to their department stores with fixed prices, assuring the public that no one would be favored nor discriminated against when purchasing a particular item.

That said, there may have been smaller shopkeepers, and perhaps British retailers who began the practice earlier than these to department store pioneers. Fixed prices were an antidote to the haggling that would frequently take place between vendor--whether an itinerant peddler or at town square market days--and a consumer.