It's been being tested in retail already (see for example: https://link.springer.com/article/10.1057/s41272-019-00224-3) and the main thing holding stores back from implementing it is that most people think discriminatory pricing is wrong. Companies are working very hard to convince us to let them do it though. Their foot in the door is offering "deals" to only certain people. You see this in things like store loyalty cards or Xbox's "just for you" prices (https://www.windowscentral.com/xbox-microsoft-store-just-for...). It's all just trying to condition us to accept that some people deserve different prices/treatment than other people.
If I were building this type of system I'd do away with electronic labels and just force people to scan a QR code with their cell phones, then use that data collected from their device to find out their income level, past purchase history, etc. then use that data to display their "price" (subject to change at any moment) right on their device along with ingredients, nutritional data, product information, ads, etc. Then I'd either generate a QR code on their device for them to scan at self-checkout, use Bluetooth to detect the device when they stood at the checkout counter, or use facial recognition. Either way, knowing what price the computer offered would be dead simple and the price of whatever is being purchased could (and probably would) change from the time you picked it off of the shelf and when it got scanned at the register. I'd be your responsibility to accept the prices or not when you pay.
If I were building this type of system I'd do away with electronic labels and just force people to scan a QR code with their cell phones, then use that data collected from their device to find out their income level, past purchase history, etc. then use that data to display their "price" (subject to change at any moment) right on their device along with ingredients, nutritional data, product information, ads, etc. Then I'd either generate a QR code on their device for them to scan at self-checkout, use Bluetooth to detect the device when they stood at the checkout counter, or use facial recognition. Either way, knowing what price the computer offered would be dead simple and the price of whatever is being purchased could (and probably would) change from the time you picked it off of the shelf and when it got scanned at the register. I'd be your responsibility to accept the prices or not when you pay.