Teaching the importance of money to the little ones is something that all parents should do to be able to show them responsibility at all times. Some simple task, some help over there in the kitchen and some money in the piggy bank.
It is a good idea to avoid some loss of bills or coins and a fun way to keep track of them. Little by little they will be grabbing practice and will be able to manage their small "expenses" in a better way in the future.