Paying large retailer workers $25k a year would cost you another $20

Mother Jones - [According to the liberal think tank Demos] increasing the average wage at large retailers from $21,000 to $25,000 would probably cost you less than $20 a year at the register yet lift some 1.5 million people out of poverty (including your cashier), create 100,000 new jobs, and boost GDP by some $13.5 billion.

...
If you are still wondering what's in it for you, however, then consider this tidbit from Sasha Abramsky:

In 2004, a year in which Walmart reported $9.1 billion in profits, the retailer's California employees collected $86 million in public assistance....In 2004, Democratic staffers of the House education and workforce committee calculated that each 200-employee Walmart 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.