Retail Scanner Data (Nielsen & Chicago Booth)

This dataset is a joint project of The James M. Kilts Center for Marketing at the University of  Chicago Booth School of Business and the Nielsen Company. This dataset describes sales by 2.6 million UPC codes and covers "more than half the total sales volume of US grocery and drug stores and more than 30 percent of all US mass merchandiser sales volume." The dataset is quite large; they suggest a machine with two TB of disk space and 16 GB of RAM.