It’d probably be the opposite. I bet they’d charge more to specific demographics - and common convenience store beverage brands would probably cost more for poorer people.

Plus, without controls, they’d probably charge different ethnic groups more for specific goods - they’d probably obuscate it somehow, like to charge white people more for something they’d probably say they were doing it because you’re a model train enthusiast or something. Or like “our consultants have told us that Tejano music fans are willing to pay a premium for coca cola” and so they jack up the price of coca cola for Mexicans without saying it’s because they’re mexican.

But yeah, I bet poorer people who have less free time would be willing to pay more for essentials because they often have less choice in where they get groceries.

Also, if poor people were charged less there’d be a whole industry of personal grocery shoppers who’d get discounted prices for rich people and charge them a service fee in exchange.