> There’s hundreds of people in the store.

Where are you shopping? I get groceries the most I've seen is 30 people at a time.

> How will the can of peas know which price to display

People are talking about facial recognition and smart phones driving this. What they're missing is that your shopping cart is likely to contain a selection of items which make it _highly unique_. Not just on the day you're shopping but across large spans of time.

Of course the lowest tech is I can just put a tracker in your cart or in your basket.