Price Per Unit

The biggest jar is not always the best deal. A 24-ounce jar of peanut butter at $5.28 works out to $0.22 per ounce. A 16-ounce jar at $3.20 is only $0.20 per ounce — the smaller jar is cheaper. Grab the big one on instinct and you overpay.

Unit price is total price divided by total quantity. It ignores package size, branding, and shelf placement to answer one question: what does a single ounce, sheet, or load actually cost? Many stores print this number on the shelf tag, but in type so small that almost nobody reads it.