Create a website that spoofs your IP address in a targeted manner when visiting online retailers - similar to the ancient practice of "remailers" that would resend your postal mail from their address.
The idea would be to have a central site - say reducethoseprices.com - that would have links to a gajillion retail websites (probably a searchable database of same) so when you surf from there via their link the destination retail site (like Home Depot) thinks your IP address is in their "cheapest price zone".
Why?
http://www.theverge.com/2012/12/24/3800472/retailers-adjusting-online-prices-depending-on-income-and-location