Try this,

Money. People fight over it and you can buy bonds with it. It's very important to every one I am sure. But it is just a piece of paper. (Explain bitcoins and how it evolved into money shortly) Then end it with something creative.

Money has had several incarnations. These have varied over time and space. A study of the evolution of money, the related circum­stances, the working of various monetary standards is fascinating. But we resist the temptation and restrict ourselves to the present. At present in India money consists of coins, paper currency, and deposit money. Coins are an example of metallic money. They are not full- bodied, but only token money, because the intrinsic (metallic) value of token coins is less than their face value. Currency notes are merely pieces of paper that have no intrinsic value of their own. They are not convertible into anything of value at a fixed rate. The issuing authority does not stand ready to buy them back against gold or silver or full-bodied gold or silver coins of equal value at a pre-determined price.