What do you think is too much interest to pay on a loan? Twenty percent? Forty percent? One hundred percent? Well, believe it or not, millions of Americans are taking out small loans at rates that can reach 400 percent a year or more.

It may sound like loan sharking, but in most of America, it’s perfectly legal, and part of a trend called payday lending.

Payday stores are among the fastest growing financial services in America now a $40 billion-a-year industry.

Ten years ago, they didn’t exist. Now, there are more than 22,000. There are more payday stores in America today than there are McDonald’s. They’re making millions of loans each year, but for many customers , the fees end up bigger than the loan.