Comment by cogman10

> the checkout counter can't distinguish who picked up which exact item.

Sure it can, cameras and facial recognition.

Identify a person when they enter the store. Track them with overhead cameras as they move throughout the store. Set the price for the individual when they get to checkout. It barely requires any extra infrastructure in most stores.

You don't need a unique barcode per item, you simply need to be able to identify the person purchasing the item at checkout.

Barcodes today don't contain price information (except for meat AFAIK. But then you'd mostly just need to change it to be weight instead of price).