https://marco.org/2007/03/13/a-big-part-of-the-lesson-of-walmart-is-that-the
A big part of the lesson of WalMart is that the commodities aren’t actually as cheap as they seem: many of the costs that WalMart avoids still must be paid by someone, and often local and state governments are the ones who pay, through channels like increased stress on emergency rooms for WalMart employees with no insurance.