The 5 worst work-at-home jobs

When it comes to finding that plum work-at-home job, here's a key ratio to consider: 50-to-1.

That's roughly the ratio between scam work-at-home jobs and actual jobs that will provide Americans with income and the type of flexibility that many need, said Sara Sutton Fell, the founder and CEO of FlexJobs, a service that links workers with telecommuting or flexible jobs.

"People want work flexibility," she said. "They want work-at-home arrangements for a lot of reasons. It could be financial, such as they can't find a job in their town, or they have a military spouse and move a lot."

With the economy still in recovery mode, many Americans remain underemployed or unemployed, which has upped the ranks of people looking to make money from working at home. Millennials are more likely to be victims of job scams than seniors, according to a FlexJobs survey, which may be due to the scarcity of good-paying jobs for younger Americans and the group's slightly higher unemployment rate.

Fell stresses that honest work-at-home jobs do exist that can help workers achieve their goals, whether that's working some extra hours or reentering the workforce while a worker's children are still young. Many of the plum jobs involve specialized skills, such as those in the info-tech industry or in editorial services.

So, how do you tell if a job is legit? Job seekers should be on the lookout for several red flags, such as asking the worker to pay for something upfront -- a computer, a startup fee or materials, for instance.

Like anything in life, if it sounds too good to be true, it probably is, Fell noted.

"Jobs that don't require skills but yet say you'll make a lot of money" are one red flag, Fell said. Scammers also pretend to be a legit, brand-name company but are only looking for consumers' personal information, such their Social Security number.

Other work-at-home jobs may be legitimate, but they might not provide the level of pay workers are hoping for.

The bottom line? Be on guard when considering a work-at-home job, and do your research.

Read on to learn about the 5 worst work-at-home jobs.

Envelope stuffing

These ads promise extremely lucrative pay for simply stuffing mailers into envelopes. One company suggests workers can make $1,200 a week for an activity that doesn't require any skill. That's a full 50 percent more than what the average full-time American worker earns currently, by the way.

What's the catch? Well, these jobs ask workers to pay an upfront fee. Red flag, anyone?

These companies actually don't have any envelopes to stuff, so workers soon find out that they have no work, according to the Federal Trade Commission. Instead, the companies ask workers to try to get other people to buy into the same envelope-stuffing dream. The original worker makes money only if she can convince other people to fall for the same line.

Assembly work

Ever see an ad that promises you can make money by assembling products at home? Well, these usually aren't good deals for workers, because some of these companies require people to buy the supplies or equipment through them.

After shelling out money for the supplies and putting together the products, the companies will often reject the items as "substandard," which means the workers don't get paid for their time and effort.

In one case, Darling Angel Pin Creations allegedly told consumers they could earn up to $500 per week making angel pins, according to the FTC. The company required the consumers to pay as much as $45 to start working, then hundreds more in supplies to make the pins. The agency noted that Darling Angel Pin Creations "rejected nearly all the angel pins consumers submitted, no matter how well made."

Rebate processing

These jobs supposedly will pay workers for helping process rebates, but the issue is that they have few, if any, rebates to process. Workers find this out after paying a fee for training or certification.

In one case, a company called Penbrook Productions allegedly told people they could make as much as $225 an hour by processing rebates, according to an FTC complaint. The catch was that Penbrook required consumers to pay an upfront fee of $197.

Once enrolled in the program, consumers found out that the work was actually setting up a website to sell products for companies, with no rebate processing as part of the work, the FTC alleged.

Medical billing

The allure of medical billing work-from-home ads is the potential to make as much as $45,000 a year, although the FTC said many of the offers misrepresent what consumers can actually earn and that the companies charge a setup fee of hundreds or thousands of dollars.

Medical billing is usually handled by large companies and is a competitive industry, so doctors and medical institutions don't typically hire consumers to handle billing from their homes. So, work or income is hard to come by after the worker shells out significant money.

In one case, consumers paid as much as almost $6,000 to a company called EDI Healthclaims, which had allegedly promised to help people make at least $1,200 a month by handling medical billing at home. The consumers lost their fees and often came away empty-handed, the FTC alleged.

Multilevel marketing

Some multilevel marketing plans are legitimate, but not all are, which is why the FTC advises consumers to be on their guard with these offers. This type of work-at-home opportunity asks consumers to sell products to other consumers through direct sales. Workers receive commissions for the sales and for sales of other people they recruit.

Some of these programs are pyramid schemes, which violate federal securities laws, according to the U.S. Securities and Exchange Commission. The agency advises consumers to be wary of programs that don't offer a real product or service and that emphasize recruitment of new workers.

In a case last year, more than 350,000 consumers were enrolled in a program called Fortune Hi-Tech Marketing that promised to help them earn significant income by selling products and services, the FTC alleged. Participants were required to pay startup costs and monthly fees to become representatives of the company, and the FTC said more than 98 percent of participants lost more money than they made.