E-Commerce is taking off in India. One of my friend runs ebay shop for second income and easily earn Rs 1 Lac per month. You don’t need huge investments to start your store. Besides ebay you can create your own e-commerce website without any hassles. Recently Shopify set shop in India. Shopify is leading E-commerce platform & provide ready solutions to launch e-commerce store i.e. no need of website designing.

You’re right Ed, it does require capital to get income from a rental property. However, I started hustling when I was a teen, baby-sitting, teaching younger kids the piano, doing homework with middle schoolers, being a French and Spanish tutor, none of which requires an initial investment. As do pet sitting, housekeeping, lawn mowing, house painting, and many gigs around.
The other point is that it is pretty easy to get started.  You don’t need to be super rich, and you don’t need a lot of time to get started.  To say it requires no time would be a lie, but you don’t need to make anything listed above your life.  You can work at your job, invest your excess income, save to buy a rental property or rent out a room in your current house, and you start a side job online without breaking a sweat.
Finally, I imagine the biggest debate with my ranking is Creating Your Own Product as the #1 passive income source. If most people have never created their own product, then it’s easy to give it a thumbs down. There won’t be much complaint about Private Equity Investing being in last place because most people are not accredited investors. But given I believe that plenty of people can create their own product if they try, pushback is inevitable because a lot of people simply don’t try!
Crowdfunding is a newer way to invest, having emerged onto the scene just within the last few years. Most people have heard of sites like Kickstarter and GoFundMe, and a very similar concept exists for real estate. Developers are always looking to raise capital to fund their projects. Through the various online platforms, investors have access to these projects and can choose to invest in both residential and commercial properties. See the List of My Favorite Crowdfunding Sites.
And, let’s face it; not everyone wants to sling body wraps or nutrition shakes to their family and friends. That’s why offering a service is often one of the best, and least uncomfortable, ways to earn side income doing something you love. Maybe you want to clean houses or rake leaves or help people file their taxes. It’s totally up to you, and that’s the beauty of this option.