The grocery store I usually visit shows the price for all of its products both per unit and (much smaller, below it) in price per kilogram. I look at that all t

The grocery store I usually visit shows the price for all of its products both per unit and (much smaller, below it) in price per kilogram. I look at that all the time, and it's often surprising which of the products is actually the cheapest, and how large the differences can be between seemingly very similar products.