Even the "price per unit" stickers on shelves are done this way. One says "price per ounce" and the larger item next to it with a different price has "price per pound."
I now buy the 2L cartons...
Fruit items in a pack (e.g. 6 oranges) - price per unit is shown.
Fruit items loose - price per weight shown.
So you can't compare which is cheaper. I assume loose...
They are sold in bulk from drawers so you can buy as much or as little as you want. (You put them in a bag and write the item number and quantity on it, and they charge you whatever you wrote.)