To find out how much a customer will save by getting a medium hot chocolate instead of a large one, you can subtract the price of the medium hot chocolate from the price of the large hot chocolate.
Price of large hot chocolate = $4.40
Price of medium hot chocolate = $4.06
Savings = Price of large hot chocolate - Price of medium hot chocolate
Savings = $4.40 - $4.06 = $0.34
A customer will save $0.34 by getting a medium hot chocolate instead of a large one.