Consumers are fiercely loyal to their favorite warehouse club. One shopper swears the fresh fruit and vegetables are better at Costco. Another consumer swears Sam’s has better prices on non-perishables.

It’s that devotion that prompted the founder of cheapism.com to dispatch a team of researchers on shopping sprees at both chains. The shoppers filled carts at both places with the same items and compared prices.

“We filled a shopping cart with products for a family of four. The total came out lower at Sam’s Club, $12 lower than Costco” said Cheapsim CEO Max Levitte.

The researchers also compared other departments like photo, optical, electronics and automotive supplies.

“If you want to buy a new car or get car insurance perhaps you want to go with Costco,” said Levitte.

The take away from the cheapism. com survey is that shoppers need to identify what items they buy most often and then look and see which store offers the lowest prices.

The stores also have different payment plans, various membership pricing and different store hours. All those should be factors in deciding what best suits your needs.