Millionaires don’t always start with a big inheritance, a tech startup, or Wall Street credentials. Sometimes, they begin with a side hustle; just a few hours a week, a little extra income, and a willingness to try something most people overlook. These tiny ideas often come from everyday life: a hobby, or something they knew they could do better.
What separates these stories from the usual “make money fast” pitches is that they grew gradually, quietly. These part-time gigs didn’t promise the moon but ended up building entire empires. In many cases, the people behind them weren’t chasing millions. They were trying to pay off a credit card, cover daycare, or buy back their time. That humble start gave them room to build without pressure. Below are 10 often-overlooked side hustles that quietly made people millionaires.
1. Parking Lot Cleanup Services
Brian Winch from Calgary, Canada built a million-dollar business cleaning parking lots with a broom and a trash bag.
He started in 1981 with a side hustle cleaning shopping center lots before dawn. The work was low-tech but high in demand; property managers needed clean lots, and he offered a cheaper alternative to janitorial companies. Over time, Brian refined his process, landed recurring contracts, and built Cleanlots into a six-figure operation.
What made it powerful? Recurring revenue, low overhead, and work that didn’t require degrees or complex skills. Today, Brian also teaches others how to replicate his model and many have.
2. Vending Machine Routes
Corey Berrier started with just a few vending machines, placing them in local gyms and office spaces. What’s overlooked about vending is the ability to automate and diversify. Healthy snacks, PPE, electronics, even CBD products, and new niches keep popping up. Once Corey realized he could buy used machines, rebrand them, and negotiate high-traffic locations, the cash flow became consistent.
The key? Finding the right location is everything. Corey focused on areas with reliable foot traffic and negotiated favorable terms. Today, many vending entrepreneurs credit him with inspiring their own million-dollar routes.
3. Etsy Printables and Digital Products
Julie Berninger built a digital product empire selling printables on Etsy. Think bachelorette party games, budget trackers, or planners—simple PDFs people download instantly.
She started with one listing, priced affordably, and focused on SEO and seasonal trends. Over time, Julie earned six figures in passive income, all without printing or shipping anything. The magic here is that once a product is uploaded, it sells over and over with little maintenance.
She later co-founded Gold City Ventures, teaching others how to create and sell digital goods. Hundreds of her students have followed her playbook to five- and six-figure success.
4. Voiceover Work via Fiverr and Upwork
Mike Joseph went from recording radio bumpers to building a thriving voiceover business on Fiverr. He wasn’t chasing Hollywood gigs; he focused on corporate training videos, YouTube ads, and IVR phone systems.
He started by recording with a basic setup at home. As his reviews piled up, so did orders. Eventually, Mike was making over $10,000 a month. He reinvested in gear and professional coaching to improve his voice and range.
He didn’t wait for permission; he created a profile, recorded a few demos, and let the market find him. It worked and he scaled to a full-time voice business in under a year.
5. Niche YouTube Channels
Graham Stephan, a former real estate agent, launched a YouTube channel to share financial tips. It started as a weekend project; just Graham in front of a camera breaking down real estate commissions and credit scores.
He now makes millions annually from YouTube ad revenue, sponsorships, and affiliate deals.
His videos are often low-frills and filmed at home. No fancy editing. Just trust-building content.
And he’s not alone. Dozens of creators in niche spaces, personal finance, gardening, and productivity earn six and seven figures annually just by sharing knowledge and building loyal audiences.
6. Airbnb Rental Arbitrage
Jasper Ribbers turned Airbnb rentals into a full-time business without owning a single property. He mastered rental arbitrage: leasing apartments, furnishing them, and listing them short-term for travelers.
The spread between rent and nightly rates became his profit. He systemized guest check-ins, cleaning, and communication using tech tools. Within a few years, Jasper had multiple listings and trained others through his podcast and course, “Get Paid For Your Pad.”
What worked? Understanding local regulations, picking the right cities, and providing great hospitality. It’s still one of the fastest-growing paths to building cash flow if you’re willing to manage the moving parts.
7. Flipping Used Books
Peter Valley built a business sourcing cheap or free books and reselling them on Amazon. He scoured thrift stores, library sales, and online classifieds, using a scanner app to spot profitable titles.
At his peak, Peter was making $10K/month flipping books part-time. The margins were wild; buying books for $1–2 and reselling for $30+. He eventually built a team, outsourced shipping to Amazon FBA, and wrote a popular guide for aspiring book flippers.
Why did it work? It’s repeatable, scalable, and underpriced inventory is everywhere if you know what to look for.
8. Mobile Notary Services
Andre Hatchett turned mobile notary work into a six-figure side hustle and later, a course that’s helped thousands. The job? Witnessing and certifying documents like loan signings and legal forms.
He built his client base through real estate agents, title companies, and even local jails. His schedule stayed flexible, and most appointments took under 30 minutes. Once he got licensed in his state and built local SEO, the business ran like clockwork.
Andre now teaches others to earn $75–$200 per appointment with startup costs under $500. It’s one of the lowest-barrier paths to legit money with real demand.
9. Amazon Retail Arbitrage
Jessica and Cliff Larrew earned over a million dollars buying products at retail stores and flipping them on Amazon. It started with clearance items at Walmart and Target—board games, toys, tools anything discounted.
They scanned items with the Amazon Seller app, checked profit margins, and listed the good ones through Fulfilled by Amazon. Within two years, they’d quit their jobs and scaled into a thriving business.
Their edge? Speed, timing, and reinvestment. They didn’t wait to build their own brand. They tapped into existing demand and let Amazon do the heavy lifting.
10. ATM Ownership
ATM machines are one of those money-making tools hiding in plain sight. You’ve seen them in convenience stores, gas stations, and nightclubs, but did you know that most of them aren’t owned by banks? They’re often owned by individuals like Mike Brown, a former police officer in Los Angeles who started placing ATMs in local businesses. Every time someone withdraws cash, he earns a small fee multiplied across dozens of machines, that adds up fast.
The beauty of this hustle is the passive income potential. Once you’ve installed the machine, loaded it with cash, and set up digital monitoring, you don’t need to be physically present. You’re essentially earning while sleeping, grocery shopping, or sitting in traffic. Of course, it does require upfront investment and a bit of groundwork to secure locations and permissions, but after that, it runs like a well-oiled machine.
ATM ownership works best in areas where cash is still commonly used such as barber shops, food trucks, or independent retailers. Over time, you can expand to multiple machines, and even lease them to others. It’s not glamorous, but it’s profitable and that’s the name of the game.