Costco:$9.99 for six 12-count packages, 88.8 oz. (11.3 cents/oz.) Kroger:$5.49 for one 24-count package, 29.6 oz. (18.5 cents/oz.) Savings at Costco:39% (7.2 cents/oz.) urbanbuzz/shutterstock Diet Coke Costco:$10 for 35 12 oz. cans (2.4 cents/fl. oz.) Kroger:$5.49 for 12 ...