"In 2004, a year in which Wal-Mart reported $9.1 billion in profits, the retailer's California employees collected $86 million in public assistance, according to researchers at the University of California-Berkeley. [...]In 2004, Democratic staffers of the House education and workforce committee calculated that each 200-employee Wal-Mart store costs taxpayers an average of more than $400,000 a year, based on entitlements ranging from energy-assistance grants to Medicaid to food stamps to WIC—the federal program that provides food to low-income women with children."

http://motherjones.com/politics/2009/01/america-195-week

And this is with a minimum wage.