For example, it is proportionately more expensive to buy a large jar of Sacla pesto that a small one. Also the cheapest way to buy cat food cans at my local Tesco is to buy them singly (only 3 varieties available). Next is the 6 can pack, and most expensive of all by the kilo is the 12 can pack.
This seems crazy to me, and calculated to trip up shoppers who are less tight arsed than me. Has anyone else noticed this?