If you have a spare bedroom, you can find a roommate or list the space on AirBnB for travelers. Having a roommate is the more passive of the two, as being an Airbnb host will require more work in the form of turning over the room between stays. This is a super painless way to earn $500 to $1,000 a month without much effort – you may even be able to cover your mortgage payment with this extra income!

Investing in bonds: Similarly, bonds are an attractive way to engage in passive income. Over a recent 45-year period, bonds funds, as measured by Vanguard Funds, returned 7.1%. Of course, there's no guarantee that investments in stocks or bonds will always work out well, investing in them is by far the surest way to generate money through passive income.
More and more companies and startups especially are embracing remote work—where you use online collaboration and communication tools to do your work from wherever you want. And you don’t have to be a 20-something hotshot designer or coder to reap the benefits of working remotely. Many remote positions are for customer support positions or other customer-facing positions that don’t require specialized skill sets.
When it comes to at-home income, selling your unwanted stuff is the definition of “low-hanging fruit.” Even if you’re resolutely intentional in your purchasing habits, you surely have possessions that you can do without: old kids’ clothing and toys, disused sporting goods, out-of-fashion wardrobe accessories, electronics, entertainment, valuable but non-sentimental keepsakes such as watches and jewelry, broken-in furniture, dusty tools and outdoor equipment, and perhaps even big-ticket items like a motorcycle or second car.