Robert Schenk, PhD
Price Elasticity
This site offers a good description of price elasticity of demand for a good, and gives examples of which kinds of goods may be elastic or inelastic.
Other
Price Elasticity of Demand
This site gives easy to understand definitions of price elasticity, along with examples, formulas, and factors determining elasticity.
Other
Economics of Health Care: Price Elasticity of Demand
This site provides a thorough analysis of the concept of elasticity, and uses an example in the health care industry.
Khan Academy
Khan Academy: Elasticity and Tax Revenue
Read about how elasticity affects tax revenue. This resource is designed for students who are taking a college-level microeconomics course.