"The guarantees typically require shoppers to provide proof of a lower advertised price on an identical item in stock at a nearby competitor’s store before a price match will be approved. However, many big-box retailers work directly with manufacturers and sell products with unique model numbers. As a result, the retailer can deny a price-match request, as no other store carries an "identical" item. Other common reasons for denial: the competitor is not "local," the ad lists a percent discount rather than a specific price, or the customer doesn't offer acceptable proof of the competitor's price.[9] Even if all criteria are met, retailers grant price-matching requests on a case-by-case basis at the discretion of store employees."
https://en.wikipedia.org/wiki/Price-based_selling#Price-matc...