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.
He earns a base salary of $7.25 an hour when he is prepping or doing other chores, but that drops to $4.50 an hour when he goes out on a delivery because he is supposed to also earn tips.
The Department of Labor allows tipped employees to be paid a base salary that is below minimum wage, but the employer must be able to show the employee receives minimum wage when tips are included.
(Read More: 6% Unemployment Rate Still 3 Years Away—Bernanke)
In the past few years, White has relied on help from his church when he couldn't pay his electric or phone bill, or needed car repairs. His fellow parishioners also helped him pick up odd jobs.
He gets $135 a month in food stamps, now known as SNAP, but lost his state-subsidized health insurance after he got his pizza delivery job. A lifelong bachelor, he lives in a family home in Robesonia, Pa., that he and his sibling inherited.
White's wages have fallen steadily over the past decade. He worked in a warehouse of a regional department store for nearly 14 years and was earning $12.50 an hour before he was let go in 2003 after a dispute with a co-worker.
He was unemployed for about half a year until he got a job as a security guard in 2004. He earned $10.60 an hour in that job, and held it for six years until he was let go in June of 2010.
(Watch NBC Video: "The needs are now"—John White)
He's been in the part-time pizza delivery job for nearly a year, but his financial situation remains precarious.
He's hoping to pick up more hours. But unlike steadier jobs he's had in the past, he's learned that with this kind of job, there's no guarantee of stable hours.
"You don't even get eight hours in one day, (and) you might be lucky to get eight hours in one week," he said.
Hoping for a Better Future
Dupont didn't expect her working life to start out this way. She graduated from high school in 2006, a year after her father passed away, got a job and moved out of the family home.
But Dupont soon found that she couldn't earn enough money to live on her own. She also needed to be home to help her mother, who is disabled and can't drive because she has seizures.
Without her father's income, Dupont and her mother couldn't keep up on house payments, and the home they'd lived in since 1998 went into foreclosure in 2009. They moved into an apartment and now live on Dupont's salary and her mother's disability benefits and food stamps.
In January, Dupont started taking classes at Houston Community College, where she is in the business technology and computer science programs.
She took out a $3,500 student loan but is hoping that she can use scholarships and grants, or perhaps find a second job, to avoid taking on more debt.
On her days off, she'll sometimes spend six hours studying, working ahead two or three weeks in her classes because she enjoys it so much.
"It tells me that there's more than what I'm doing now out there – there's more to life than this," she said.