My son's piggy bank

My money saving habits are slowly rubbing off on my son.  When he does his chores, I usually give him at least a nickel, sometimes a quarter, and he puts it in his piggy bank.  Some days he will look for ways to earn money.  The funny part is if you ask him what he is saving his money for, he will tell you, "A truck."  And he's not talking about a toy truck.  He's only four, but he's so smart.  Maybe it is about time to teach him about the concept of money, because he has no idea how many quarters he will need to buy a truck.