US Department of Labor
Bureau of Labor Statistics: Spending Patterns of High Income Households [Pdf]
An article, chart, and graph compares spending habits for hourseholds that bring in over $90,000 with those that bring in under $90,000. (Nov. 1998)
Khan Academy
Khan Academy: Lesson Overview Cross Price Elasticity/income Elasticity of Demand
In a previous lesson we learned about price elasticity of demand, but there are many other types of elasticity that measure how agents respond to variables other than the change in a good's price. Two of these are Cross Price Elasticity...