These days, anyone with a smartphone or computer has access to tons of ways to bring in extra cash -- including many that are surprising and unusual.
Here are 10 of the oddest side gig opportunities in the 21st-century economy.
1. Get paid to lose weight
If you need some extra motivation to drop those last few unwanted pounds, the idea of fattening up your bank account may do the trick.
These sites generally work in the form of a wager. Participants put up money and bet they can lose weight. If they succeed, they win all or part of the pot; if not, they lose their ante.
2. Get paid to watch videos
If you enjoy watching videos, you could make money doing it. The makers of online videos are always looking for feedback, and they are willing to part with some serious cash to make it happen.
InboxDollars is one of the most popular video-watching sites, but there are others. Some movie studios even offer cash for in-home previews.
You may not get rich, but you will have some extra cash — and potentially get to check out lots of fun content.
3. Be a human guinea pig
You need a bit of courage to make this one work, but a side gig as a human guinea pig could be a lucrative one.
Drug companies are on the lookout for healthy individuals to test the efficacy of their new pharmaceuticals, and the amounts they pay can be quite generous.
Obviously, there is some risk, but plenty of people use clinical trials to bring in a side income. Potential study participants can search for trials in their area by going to ClinicalTrials.gov.
4. Play video games
Are you an ardent gamer? If so, you could turn your passion into some cash. Game developers are anxious for feedback from ordinary people, and are willing to pay for impartial advice.
One of the most popular ways for game enthusiasts to make extra money is through an app called appKarma. Users earn points for watching videos, playing games and giving feedback.
Those points can be redeemed for modest amounts of cash via PayPal, or for somewhat larger rewards in the form of gift cards.
5. Get cash back from online purchases
You shop anyway, so why not get paid for it? There are plenty of places to sign up for money-saving coupons, rebates and cash-back opportunities, and the sooner you get started, the sooner you can start profiting.
The Paribus app tracks your online purchases, scans for lower prices and refunds the difference when it finds a better deal.
6. Become a product tester
What could be better than trying out new products before the rest of the public, right? When you become a product tester, you might get to enjoy some great food, exceptional cleaning products and other items — and put money in your pocket in the process.
When consumer brands release new products, they want to test them first, and they do so through a network of focus groups and product testing companies.
7. Do your neighbors' laundry
If you have a washing machine, you could make extra money by taking in laundry for your busy neighbors. Many people — especially those who work hectic schedules — would be more than happy to farm out this tedious task.
You might spread the word about your laundry-for-hire service at church, on the bulletin board at the grocery store or via an online classified ad.
Once you land your first set of clients, word-of-mouth advertising about your excellent washing and folding techniques will help you expand your business.
8. Profit from your camera skills
Today, everyone with a smartphone is a photographer, but some have better skills than others. If you are adept with a camera, you could sell your shots to advertisers, owners of online stores and anyone else needing quality photography.
Stock imaging sites such as Shutterstock give talented photographers a chance to post their favorite pics. When someone downloads one of your shots, you share in the proceeds.
Shutterstock pays photogs 25 cents for each download, though you can earn more if your work becomes popular. You may not get rich, but you can bring in a little bit of cash doing something you love.
9. Open a new bank account
Did you know that some banks will pay you to open a new account? The bonus offers can be quite enticing: as much as $250 or even $500, depending on how much you deposit and the rules of the promotion.
Some bonus offers are predicated on a specific opening deposit, while others also require an ongoing direct deposit.
Be sure to read the fine print carefully, but if you meet the requirements, you could pocket hundreds of dollars over the course of a single year.
10. Care for others
If you have a background in nursing or have worked as a caregiver, you can parlay your skills and compassion into a great part-time job. Several websites and agencies bring together eligible caregivers with families who need them.
You will need a solid background as a caregiver — possibly certification, too — but for those who qualify, this could be a great opportunity. You can can choose your clients, set your own hours and know you're making a difference while making money.
If you're already acting as a caregiver for a family member, government programs and insurance may provide money for the work you're doing for your loved one. AARP has tips on how to get paid.