There are countless ways to earn extra income. You can take on a part-time or full-time job, work online or offline, or pursue flexible, unconventional opportunities that fit your schedule and skills.
Side income can be useful for covering unexpected expenses, paying down debt, saving toward a goal, or simply adding variety to your work life. If you’re curious about branching out, there are plenty of options to explore.
If you want real-life examples, consider reading 10 Things I’ve Done To Make Extra Money to see ways the author has generated additional income. And remember: even without a blog, you can monetize active social media accounts on platforms like Twitter and Instagram.
Below are four unusual — but legitimate — side income ideas to consider:
1. Get paid to sleep.
One surprising option is participating in sleep studies, such as those run by research institutions like NASA. These studies investigate how prolonged bed rest and other conditions mimic the physiological effects of space travel. Participants can be compensated well: some programs have paid up to $18,000 for a 70-day study.
In such protocols, you typically remain in bed for the duration of the study, including for showering and bathroom breaks. The research helps scientists understand how weightlessness and prolonged immobility affect the human body, which in turn informs astronaut health during space missions.
While the idea of staying confined to bed for weeks may be tough for many people — losing sunlight, mobility, and routine can be mentally and physically challenging — the compensation can make it worthwhile for some. Accepted participants in certain studies have been paid around $1,200 per week for their time.
2. Donate stool samples for compensation.
It may sound odd, but donating stool for medical research or therapeutic uses is a genuine way to earn money. Organizations that supply stool for fecal microbiota transplants to treat severe infections like C. difficile need healthy donors and may pay well for reliable contributors.
Because donors must meet strict health criteria, only a small percentage of applicants pass screening. When accepted, donors are compensated per sample — for example, some programs pay around $40 per sample, with bonuses for frequent donors. Donors who provide samples several times per week can increase their earnings substantially; reports indicate donors can make several thousand dollars a year depending on frequency and program structure.
These programs exist because healthy donor material can be critical to treating patients with life-threatening bacterial infections. If you’re considering this option, research the specific requirements and commitments of any clinic or company thoroughly.
3. Rent yourself out as a companion or friend.
Websites that connect people seeking companionship with local hosts have grown in popularity. Platforms like RentAFriend allow users to advertise their availability for platonic, paid companionship — attending events, accompanying someone to dinner, serving as a workout buddy, or simply spending time together in social situations.
These services explicitly prohibit romantic or sexual encounters and focus on social, platonic interactions. Earnings vary widely: some people treat this as a part-time gig, making a few hundred dollars on weekends, while others report more consistent, higher income if they work frequently and build a strong client base. Listings typically display hourly or per-event rates set by the friend providing the service.
If you’re outgoing, reliable, and good at social interactions, this may be an accessible, flexible side income option. As with any peer-to-peer service, be mindful of safety, set clear boundaries, and communicate expectations up front.
4. Rent out your car when you’re not using it.
Car-sharing and peer-to-peer rental platforms make it possible to earn money by renting your vehicle to others hourly, daily, or for longer periods. If your car spends a lot of time idle, renting it out can turn an unused asset into a revenue source.
Potential earnings depend on vehicle type, location, and rental duration — rates can range from modest hourly fees to over $100 per rental session for high-demand vehicles or longer-term bookings. Before listing your car, check with your insurance provider and the rental platform about coverage and liability. Expect some wear and tear; many platforms offer protections and insurance options, but it’s important to understand the terms.
Car rental can be one of the simpler passive income ideas if you’re comfortable sharing your vehicle and have a reliable process for handoffs and maintenance.
How far would you go to earn side income? Which of these ideas would you consider, and which would you decline?