Reach Upward has a great post on the economics involved in "Shopping Local". His post features a replay of a concept proposed 50 years ago by an economist by the name of Leonard Read, and made famous by Milton Friedman.
The concept is that something as simple as a lead pencil could not be made by any one man. In fact, its production involves the work of countless people. The idea was intriguing enough to me that I've started a new blog dedicated to gathering all information on the production of pencils.
Check it out.
Make One Pencil