Crystal Dupont knows what it's like to try to live on the federal minimum wage.
Dupont has no health insurance, so she hasn't seen a doctor in two years. She's behind on her car payments, and has taken out pawn shop and payday loans to cover other monthly expenses. She eats beans and oatmeal when her food budget gets low.
When she got her tax refund recently, she used the money to get ahead on her light bill.
"I try to live within my means, but sometimes you just can't," said Dupont, 25. The Houston resident works 30 to 40 hours a week taking customer service calls, earning between $7.25 and $8 an hour. That came to about $15,000 last year.
It's a wage she's lived on for a while now, but just barely.
About 3.6 million Americans were earning at or below the federal minimum wage of $7.25 an hour in 2012, and those weren't all high school students flipping burgers.
About half of them were 25 or older, a little more than one-third were working full time and a little less than three-fourths had graduated from high school, according to the most recent government data.
A person working full time for minimum wage would take home an annual salary of $15,080. That's a shade higher than the poverty threshold for a household containing two adults, and about $8,000 less than the poverty line for a family of four.
These are the workers who answer your customer service calls, deliver your pizzas, take care of your children, bag your groceries and serve your food.
President Barack Obama has called on Congress to give them a raise by increasing the minimum wage to $9 an hour by 2015.
Liberal-leaning economists say the move would help millions of workers without better prospects pay their bills. It would also pump more money into the economy through higher consumer spending, they argue.
(Read More: Raising Minimum Wage Would Ease Income Gap but Carries Political Risks)
"Unfortunately, for far too many people, the ladder that they're on doesn't have a whole lot of rungs," said Doug Hall, director of the Economic Analysis and Research Network at the progressive Economic Policy Institute.
But conservative thinkers argue the move would hurt both the economy and low-wage workers. They say employers would have to cut benefits or jobs so they could afford to pay the higher wages to remaining employees. Some say the minimum wage already keeps people out of a job.
"There (are) the people who are already working and are getting the minimum wage, and there's the other group of people who are not working because of the minimum wage," said Mark Perry, a scholar at the conservative American Enterprise Institute.
Caught in the middle of this debate are the workers themselves, millions of whom are preoccupied with the daily worries of getting by.
Workers like John White, 61.
"It's by the grace of God that I am having ends meet," said White, who was out of work for 20 months before he got his current, part-time job delivering pizzas. He has relied heavily on his church for financial and other support.
White has applied for a number of jobs, but he worries that at his age he is often overlooked for younger, more highly trained workers.