If you’re looking for inspiration, my friend Michelle Schroeder-Gardner of the website Making Sense of Sense has become the expert on all things affiliate marketing. Michelle earns more than $100,000 per month from her blog and the bulk of her income comes from affiliate sales. Michelle has had so much success with affiliate marketing that she even has her own course called Making Sense of Affiliate Marketing.
But don't make the mistake of thinking this will be a passive source of income—you're on call whenever you have a guest and you'll always need to keep the place clean for incoming visitors. On top of just renting on Airbnb, consider offering your guests paid add-ons, like Lauren Gheysens', Royal Day Out in London, England—where she gives visitors a local's only tour of the city, complete with bespoke 18th century costumes.
Get samples. When you first start out as a freelance writer, it can be hard to get work without any published samples. However, it is possible to get quality samples if you are willing to do some writing for free. First, you can publish content on your own blog or website. Also, you can write guest posts for someone else’s blog. Finally, you can write blog posts for free in exchange for a byline.
As of 2012, estimates suggest that over fifty million U.S. workers (about 40% of the working population) could work from home at least part of the time, but in 2008 only 2.5 million employees, excluding the self-employed, considered their home to be their primary place of business. The number of employees reported to have worked from their home "on their primary job" in 2010 has been reported as 9.4 million (6.6% of the workforce), though, this number might include the self-employed. As of 2017, roughly 3.7 million employees—2.8% of the workforce—work from home at least half the time, Global Analytics Workplace reports. Very few companies employ large numbers of home-based full-time staff. The call center industry is one notable exception: several U.S. call centers employ thousands of home-based workers. For many employees, the option to work from home is available as an employee benefit but most participants only do so a fraction of the time. Top paid among work-from-home sectors are home-based physicians and radiologists in which it is suspected that they earn near the $1,975 median weekly income of physicians, as reported by the U.S. Bureau of Labor Statistics, making it a six-figure job. Studies show that at-home workers are willing to earn up to 30% less and experience heightened productivity. 
If you can create a regular audience for your podcast on a specific topic, this is a great way to get sponsors and fund this side business idea. My podcast, The Side Hustle Project is actually my current side business idea, and because I had an existing audience here on my blog at the time I launched the show, I was able to broker a $5,000 sponsorship from Freshbooks to place ads on the first ten episodes before I even got started.
What does that mean for you? It means Nielsen will pay you $50 a year to keep their app on your favorite internet browsing device. The app itself collects statistics on your internet usage anonymously, so you never have to worry about any data being linked to you. And the best part is, the app takes up barely any space and doesn’t slow down your phone or tablet at all!