How the Sears Catalog Undermined White Supremacy in the Jim Crow South
kottke.org
kottke.org
One area where poorer people do get charged more is for loans.
https://www.bloomberg.com/graphics/2016-amazon-same-day/
https://www.reuters.com/article/us-amazon-com-jobs-automatio...
edit: Googling for "the history of sears" brings up a site named Sears Archives. I can't tell if it is official or not, but it does seem to be very comprehensive: http://www.searsarchives.com/