Understanding how aggregate demand is different from demand for a specific good or service. Justifications for the aggregate demand curve being downward sloping More free lessons at: http://www.khanacademy.org/video?v=oLhohwfwf_U

Looking at the supply curve as an opportunity cost curve. Understanding the producer surplus as the area between the supply curve and the market price More free lessons at: http://www.khanacademy.org/video?v=-V-Y5klejSg

How the price of inputs, price of related goods, number of suppliers technology, and expected future prices affects the supply curve More free lessons at: http://www.khanacademy.org/video?v=0isM0GF-rMI