NPR interviews the author of Turning Poverty into a Multibillion-Dollar Industry. I had no idea what a payday lender was prior to reading this, let alone that there's a whole industry around that. The worrisome part, as the author reports, is that big/too big to fail banks are part of this industry ("it's the main banks, from Goldman Sachs to Wells Fargo to Wachovia to Bank of America and Citibank — that funded these industries").
Payday lenders don't want to admit that."They tend to cast themselves as noble. You know, 'We're in neighborhoods doing business where others don't go.' It's almost heroic". And: ""Until recently, they were making profit margins of 20 percent to 25 percent a year"

Book info:
Broke, USA: From Pawnshops to Poverty, Inc. — How the Working Poor Became Big Business by Gary Rivlin