An age old custom exists in the United Kingdom (not sure about anywhere else in he world though). When a child loses one of its milk teeth, the said tooth is placed under the childs pillow, and upon awakening after a nights sleep, a shiny coin has replaced it.
The phenomenon is atributted to the tooth fairy.
A friend of mine searched the web to find the current rate of exchange for milk teeth, and discovered this:
http://www.abarnett.demon.co.uk/atheism/tooth.htmlA friend of mine fell asleep withhis head uder the pillow, awoke the next morning; no teeth and £16.50 in small change under the pillow.