Let's find what each cost at one pound. Let's name the 5-ounce can can A, and the 11 ounce can can B.
Can A:
0.85÷5
0.17
Can B:
2.20÷11
0.20
So if you compare each price, 0.17< 0.20, which is Can A<Can B
So the 5-ounce can cost less, which is a better buy.