Introduction to Economics at UC Berkeley
Demand and supply
http://www.youtube.com/watch?v=ZR2255CEhvk
http://www.youtube.com/watch?v=iLpeK-gQ_I8

Applying supply and demand MIT
http://ocw.mit.edu/courses/economics/14-01sc-principles-of-microeconomics-fall-2011/unit-1-supply-and-demand/applying-supply-and-demand/

The invisible hand and much much more from the OU- an overview of Economics
60 second adventure in Economics
http://www.youtube.com/watch?v=LCRNI04tnN8

Introduction to Microeconomics MIT
http://ocw.mit.edu/courses/economics/14-01sc-principles-of-microeconomics-fall-2011/unit-1-supply-and-demand/introduction-to-microeconomics/