DOTHAN, Ala. -- One recent morning, dozens of elderly and disabled people, some propped on walkers and canes, gathered at Small Loans Inc. Many had borrowed money from Small Loans and turned over their Social Security benefits to pay back the high-interest lender. Now they were waiting for their "allowance" -- their monthly check, minus Small Loans' cut.

The crowd represents the newest twist for a fast-growing industry -- lenders that make high-interest loans, often called "payday" loans, that are secured by upcoming paychecks....