Customers wait to pay for merchandise at a Dollar General store in Creve Coeur, Illinois.

It was finally starting to look like the lowest-earning Americans had caught a break.

Yet as they feel the squeeze of rising health-care and housing costs, the lift from a stronger job market and low fuel prices hasn't been enough for these consumers to feel relief. And for hundreds of thousands who are unemployed, a change in qualifications for Supplemental Nutrition Assistance Program benefits is making it even tougher to put food on the table.