Curated OER
Market Demand for Goods and Services
This is an easy to understand site that presents the law of demand, changes in quantity demanded, and the factors that cause a demand curve to shift. It also discusses how inferior goods and normal goods respond to changes in demand.
Curated OER
Demand Curve, Mr, and Ar Curves Under Alternative Output Markets
This site provides a good analysis of the concepts of marginal product, marginal revenue product, marginal costs, and how a monopsonist determines wages and quantity of labor hired.