New Strategist Press Publications
UMaine has ebooks from New Strategist Press (listed below) that have extensive marketing data on many different demographic groups. Here's a screen cap of a page from its book about Generation X.
Statista has data about many different demographic groups and their commercial behavior, both general and specific. Here's a screen grab from Statista's report on Generation X and their grocery shopping habits.
Consumer Expenditure Survey (Bureau of Labor Statistics)
Provides information on the buying habits of American consumers.
RKMA Market Research Handbooks - These downloadable market research handbooks cover many different market sectors. Each report breaks down into industry segments and covers market assessment, trends, demographics and more.
Best Customers by New Strategist Press Editors - These data reports are collected from the Bureau of Labor Statistics' 2014 Consumer Expenditure Survey, this report analyzes the demographics of household spending on hundreds of products and services. Identifies which households spend the most on those products and services, and which control the largest share of spending. Also included is a product-by-product analysis of spending trends before and after the Great Recession, and a prediction of future trends