Each product on a grocery shelf should have a label beneath it. This label has the Retail price, Unit price – price per until amount (ounces, pounds, etc.), Name of Item and the size of the package.
We all tend to look at the actual price and grab the cheapest one or our favorite brand. Instead of looking at the item price, the unit price is the quickest and easiest way to comparison shop. For example, I was shopping for toilet paper this weekend at Office Depot. A pack of Kleenex Cottonelle 10 pack was $10.99. A pack of Charmin Basic with 6 rolls was $7.69 and a pack of Marcal with 16 rolls was $12.99. Doing some quick math it would seem the Marcal is the best buy. To be sure, I checked the unit price and the price tags showed that the Cottonelle was $1.10 per roll, the Charmin basic was $1.28 per roll and the Marcal was indeed the best price at just .81 per roll.