Expensive face creams

Who knew that creams for your face could be so expensive!  I'm going to have to rethink what to buy for my mom.  Which of these high priced cremes is most expensive? In this activity students observe some prices of facial moisturizers; choose one and calculate its price per fluid ounce (volume - not weight); and use that rate to calculate the cost of some more common products like milk and gasoline.  For a finally they look into scorpion venom.