Building Sustainable Wealth: 24 Passive Income Methods Recommended by Erika Kullberg

Millions of Americans are ditching the 9-to-5 grind and turning to passive income to build sustainable wealth. Erika Kullberg, a personal finance expert and former lawyer, boastsover 21 million followers across various social media platforms, particularly Instagram and YouTube.

She gained significant traction by sharing financial tips and insights, ultimately becoming a well-known figure in the personal finance space.Her content focuses on practical strategies for saving money, managing debt, and making informed financial decisions.

Erika’sguidancehashelpedregularpeople break free from paycheck-to-paycheck living.Today, she’s revealing the top 24 passive income methods that areworking in 2025.

High-Yield Savings Accounts with Bonus Offers

High-yield savings accounts are one of theeasiestandsafestways to grow your money without lifting a finger. Online banks like SoFi, Ally, and Marcus by Goldman Sachs arepaying4.5%APYor higher. Erika Kullbergpointsoutthat automation—puttingmoneyinto these accountsweekly or monthlygeneratesconsistent, hands-off wealth.

Print-on-Demand Merchandise

Turn your creativity into money with print-on-demand (POD) sites like TeeSpring, Printful, and Redbubble. You create it once, and the website handles the rest—printing, shipping, customer service, and payment processing. “This is one of the lowest-barrier passive income models for artists, designers, and meme-makers,” Erika says.

To drive visibility, the most successful sellers often use trending niches like zodiac signs, pet humor, or inspirational quotes. Average monthly earnings range from $200 to $2,000, depending on your niche, design quality, and marketing audience. POD income is passive once set up, and you can scale quickly by introducing new designs every week.

Pro tip: Combine this with AI tools like Canva or Midjourney for quick design generation.

Selling Digital Downloads on Etsy

If you have design or organizational talent, selling digital downloads on Etsy is an excellent passive income stream. From planners and calendars to digital art prints, the possibilities are endless. Erika loves digital downloads because they’re easy to create once and then sell again.

No physicalitems, and you can automatefrom listing to delivery,perfect for busy entrepreneurs. Successful Etsy sellers in 2025 earn anywhere from $500 to $5,000/month, depending ontheniche andhowwell you market.

Pro tip: Keywords involving trending topics (minimalism, sustainability, or budgeting) boost visibility. If you’re tech-savvy, you can utilize tools like Canva and Adobe Spark to easily and effectively design products, which is a low-investment, scalable passive income stream.

Automated Dropshipping with AI

Dropshipping became a trend for building an e-commerce business without managing inventory, and now AI-powered tools are making it even easier. Shopify, AutoDS, and DSers are some platforms that merge automation with product research, order fulfillment, and monitoring.

As AI became more sophisticated in 2025, dropshipping success rates increased with less hands-on involvement from sellers. Erika suggests that beginners start with a niche market—think eco-friendly products, electronics, or pet supplies—to avoid competitive markets. 

“The secret is to let the systems do the heavy lifting and focus on optimizing your ads and customer experience,” she says. Automated dropshipping combined with AI is a highly fast-growing passive income system for 2025.

Peer-to-Peer Lending Platforms

Peer-to-peerlendingwebsiteslike LendingClub and Prosper allow you to earnmoneyby lendingtosmallbusinessesorindividualsand earning interest.Thesitesconnect lenders with borrowers, cutting out thebanking middleman.

P2P lending can yield 5% to 9% yearly returns, with some risk depending on the borrower’s creditworthiness. Erika advises investors to spread the money across several loans to mitigate the risk of defaults. If done right, it has the potential to be a solid source of passive income, especially if you diversify across loan types (personal, medical, small business).

“It’ssimilartobeing a bank, but withgreaterflexibility and potential for return,”Erikastates.

Vending Machines

Vending machines aren’t just for snacks—they can be a sneaky way to earn passive income with little work. The key to success is placing machines in high-traffic areas such as office buildings, gyms, or schools. Erika recommends starting with a handful of machines in your direct area and growing slowly as you learn the ropes.

Maintenance is minimal—replenishing and the occasional fix, which can be subcontracted to third-party vending suppliers. The best part? Vending machines require little to no supervision, and once they’re installed, they’re a hands-off source of income. They work around the clock, and you don’t even have to be there to pick up the money,” Erika says.

Monetization of aYouTube Channel

YouTube remains a popular choice for those looking to generate passive income. With over 2 billion active users, the platform offers several ways of earning money, from ads to memberships to sponsored content. Erika recommends starting a YouTube channel around a niche you’re passionate about—tech reviews, cooking lessons, or investment advice.

Once you have 1,000 subscribers and 4,000 watch hours, you can join the YouTube Partner Program and earn money from advertisements. Popular creators earn anywhere from $2,000 to $100,000 monthly, depending on viewership and advertisement clicks.

Even after the video is uploaded, it earns money as new viewers view it. “You create the content once, and YouTube works for you forever,” Erika says.

Investing in T-Bills and I-Bonds

Treasury Bills (T-Bills) and I-Bonds are ideal for risk-averse investors seeking stable, low-risk returns. T-Bills offer up to 5.1% returns in 2025, and I-Bonds, which are inflation-indexed, currently offer a competitive rate of 6.89%. These government-backed securities are safe, as the U.S. Treasury guarantees them.

Erika loves these products for their safety and simplicity—no complicated brokerage accounts necessary. Once you purchase, the interest is compounded and paid at periodic intervals, with I-Bonds offering tax advantages, too. With inflation still a concern, these bonds protect your wealth from losing purchasing power. Most financial advisors suggest holding T-Bills or I-Bonds as part of a diversified passive income portfolio.

AI Voiceovers for Content Creators

Voiceovers are a thriving business, especially with the evolution of AI-powered tools like ElevenLabs, Descript, and Lovo.ai. AI can create professional-level voiceovers with minimal effort, whether for audiobooks, podcasts, explainer videos, or virtual assistants.

Erika suggests licensing your voice ordevelopingvoices inalternativelanguages and tonesthrough AI tools, offering a truly scalablerevenuestream. Themostexciting aspectof thisprocessis that, once created, the voiceover can be usedseveraltimesacrossnumerousplatforms.

Content producers can earn passive royalties whenever their voiceovers are used or sold. “AI is the future of voice content—it’s scalable, profitable, and can run on autopilot,” says Erika.

DevelopingNiche Blogs with SEO and AdSense

Blogging is a very old and highly sustainable source of passive income, especially if paired with SEO (Search Engine Optimization) and AdSense. Bloggers drive organic traffic to their websites and earn money from advertising and affiliate links by focusing on a niche topic and creating helpful, optimized content. 

According to WordPress, niche blogs earn between $500 and $5,000 monthly, depending on traffic, and 80% of organic website traffic is driven by SEO. Erika suggests using Google Analytics to monitor which posts are generating the most traffic so you can focus on winning content.

A well-maintained blog can continue to make money long after the post is published, as long as the content remains relevant. “Create once, monetize forever,” Erika says. With the right mix of SEO, compelling content, and monetization strategies, blogging is a passive income powerhouse.

Buying and Monetizing Aged Domains

Aged domains are websites that have beenactiveon the internetfor several years and have accumulatedqualitybacklinks and SEOjuice. Buying and monetizing thesewebsitescan lead to immediate passive income throughadvertisingor affiliate links.Marketplaceslike Odys Global and Flippa allow investors tobuyquality, aged domains for a fraction of the cost ofcreatinga newwebsite.

Erika recommends usingsuchdomains for affiliate marketing or redirecting them to existing websitestogeneratemoretraffic and revenue. Some domain investorshavereported300–500%ROIwithinayear.”An aged domain is like aclassiccar—it’s worth moreovertime,”Erika says.

Licensing Your Music or Beats Online

Artists can license their beats or music on platforms like AudioJungle, BeatStars, and Pond5 and earn passive royalties every time their music is used in videos, ads, or podcasts. As music becomes increasingly integral to content creation, the demand for licensed music has skyrocketed. 

Erika suggests putting your music on multiple sites to increase visibility and sales. Depending on usage, Artists with hundreds of songs indexed can earn between $500 and $5,000/month. “It’s like being a DJ—only your mixes get played around the world, forever,” says Erika.

Licensing music is a great passive income stream for anyemergingmusician or producer.

Creating an App or SaaS Tool

The app market is thriving, and mobile app revenue is expected to reach $613 billion in 2025. Building an app or SaaS product does not require technical expertise—a platform like Bubble and Glide allows anyone to build apps without coding.

Erika recommends identifying a niche need and solving it with your app, which leads to higher retention rates. Successful apps often generate $2,000–$50,000/month, depending on user engagement. If you’re unsure where to start, platforms like Appsumo offer access to customizable and sold SaaS tools.

Investing in Cryptocurrency Staking

Cryptocurrency staking enables you to generate passive income by holding some cryptocurrencies in an electronic wallet and contributing to the security of the network. Some of the most popular coins, such as Ethereum and Polkadot, enable staking, with a 5%–15% return per annum based on the cryptocurrency and platform.  

“It’s likegettingdividends in the digital currencyspace,”Erikastates. Forthecrypto-comfortable, stakingisagreatpassive incomewithlittlerisk.

Building a Niche Product Line on Amazon FBA

Amazon’s Fulfillment by Amazon (FBA) program is an excellent source of passive income through selling physical products. Once you source or manufacture your goods, Amazon does the rest regarding warehousing, shipping, and customer service. With the FBA program, sellers can earn passive income while Amazon deals with the logistics. 

“Amazon FBA gives you the freedom tobuildwealth while Amazondoesthe heavy lifting,”says Erika.

Disclaimer: The Finance key does not provide and does not intend to provide financial, investment, tax, or legal advice. Information contained in this article is for informational and educational purposes only. This list is solely the author’s opinion based on research and publicly available information. Including links to third-party content is not an endorsement by The Finance Key of such content or services. Please do your due diligence and use your discretion.