What is the average savings at a Costco warehouse compared to a supermarket?

The average savings for consumers when they shop at Costco versus a regular supermarket is an approximate 20 percent. Consumers' Checkbook rates the overall savings at 19 percent, while financial blog Squawkfox rates the savings at 20.64 percent.

Consumers' Checkbook also rates the warehouse clubs Sam's Club and Smart & Final, with Sam's Club shoppers saving an average of 26 percent with Smart & Final customers saving only an average of 1 percent. These statistics come from products available in both stores. Squawkfox also finds good savings on frozen foods, diapers and condiments at Costco, while fresh produce and chicken are more expensive by weight.