Is one of them a much larger chain? They could be buying a lot more at once. I think some stores take a hit on staples and make up on higher margin products. I believe Walmart does that with some items.

Either way, you can't figure an issue like this out by looking at one arbitrary product between two stores in one area. Your methodology here is totally arbitrary and anecdotal.

A better way is to look at the profit margins of the most popular chains in a larger region, and profit margins for grocery stores in general are usually considered good at 3%.

3% isn't price gouging. That just meets inflation IF you believe government numbers. The grocery business is brutally competitive and low margin to the point that I can't see why anyone would want to invest in that space anymore unless they have a ton of money and a line on extremely shit quality products, or know they can move a ton of product and beat inflation somehow.

You'd be seeing a lot more people come into the space if it was as profitable as politician leeches like to claim. That isn't the case and the rhetoric is dangerously close to becoming price controls. At 3% that equates to stores closing at this point.