At Costco, the 90-ounce jug costs $9.99, or $7.99 if you catch it on sale. That’s about 11 cents an ounce. (On sale, that’s 9 cents.) At my other favorite grocery store, the largest container is only 75 ounces and costs $9.39, so buying the Costco jug is like getting 15 ounces for free! That’s a lot of dishwashing.