As cool as it is, what if the site they’re using to host goes down, or they move it? Also, if this is to “save paper” it’s way more unnecessary because the paper they used to print the QR code could’ve been used to print the price.
I would bring anything I wanted to purchase to the front and after they ring each item up decide there whether I want to pay that price or not. I would definitely not scan a QR to find out a price.
Scan QR for price is the same as "call for quote".. if you feel the need to conceal your prices then they are obviously not good, I won't waste my time confirming the obvious and simply go elsewhere.