If you’ve ever thought to yourself, “I wish there was a product that did this,” then invent it! Create a product, medical or otherwise, and sell it as a company or get royalties for it. It’s not impossible to figure out, I have many friends who have taken a concept to market. Don’t overlook an invention as a fantastic means of attaining passive income.
"People will pay to learn what you know about programming or designing, how to be a better public speaker, and or how to increase sales. How you design, develop and create your e-course will depend on what you teach, how you teach, and the best way for your readers to learn" Zelenko says. Sure, you'll spend some time and money developing your course on platforms such as Udemy.com or Teachable.com, but once you've created it, there's minimal upkeep.
Of course, there’s nothing to say you can’t do both. You can manage your own commercial real estate rentals and flip houses while you have someone else help manage residential rentals. You can invest in REITs and real estate crowdfunding. You’ll get the higher returns of active management while benefiting from the diversification and ease of passive income through other sources.
Lending Club went public in 2014 and is now worth about $1.7B. They advertise P2P lending returns of over 7% for well-diversified portfolios of over 100 notes. I’ve personally been able to achieve a 7.4% annual return over the past two years in a completely passive way by investing in A and AA notes. Others have achieved a 10% annual return through relatively minimum effort.
What I did: I first identified my favorite places in the world to live: San Francisco, Honolulu, Paris, Amsterdam, New York City, and Lake Tahoe. I then looked up the median rent and housing prices for each city. Then I factored in private education costs for two kids to be conservative given I may not have two kids and public schools are often good enough. After calculating all vital costs, I then did a self-assessment of how happy I was making $50,000, $100,000, $150,000, $200,000, $250,000, $350,000, $500,000, and $750,000. I decided working 20 hours a week making $200,000 a year is the best income balance for maximum happiness. 
First: I understand why you would say that such investments are restricted to only accredited investors, because generally, that’s true. There are means, under federal securities regulations and Blue Sky laws in each state, to sell interests to non-accredited investors – but usually those means are so heavily regulated and involve disclosures so similar to cumbersome registration requirements that it is not worth it for the seller to offer to non-accredited investors.
If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.
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