It all started a long time ago... Night watchmen in Ancient China would blow into the tops of acorns to alert the towns to invading Mongolians, in the third century. Later, when China established the concept of seigniorage, they would use coins to recognize only the most astute of acorn blowers.

Of course, in ancient Egypt two blades of the papyrus plant along the Nile river were held together in between the palms. By blowing into the palms the papyrus leaves would make a loud vibrant sound, a sound that remarkably resembled the titillating sounds of coins falling from ones hand onto a pyramid.

Of course, don't take my word for it, Google seems to have a different perspective.