The 6-ounce package costs 0.37 per ounce. The 15-ounce package costs 0.39 per ounce. The 26-ounce package costs 0.36 per ounce. To figure this out, I took the cost and divided it by how many ounces there were in the package.
ANSWER: the best buy is the 26-ounce package because each ounce costs less.