Etsy: While Etsy's popularity has declined recently, it's still a great resource for selling handmade items online. No need for complex ecommerce sites or merchant accounts or any sort of automation. The company takes a commission of every sale and charges a small listing fee per item. But many still use Etsy as their primary source of income. The best part is that you can also sell digital products on here such as poster designs.
Teaching and tutoring English as a second language is a great way to make money online, not to mention open some doors for you to travel the world if you'd like. While full ESL (English as a Second Language) accreditation is recommended, as long as you’re a native speaker and have the ability to teach, there are people in countries such as Hong Kong or the UAE who are willing to pay upwards of $25/hr for you to tutor them English via Skype. Check out Indeed, Learn4Good and Remote.co for remote english tutoring jobs or sign up on a specialized site like VerbalPlanet or Chegg Tutors.
If you already have a website that's driving in targeted traffic, a great way to make passive income from the content you're already creating as an easy side business idea, is through affiliate marketing. ShareASale, Rakuten, Clickbank, and Skimlinks are a few of the best affiliate networks and tools that can help you make money from the content you already produce, thus amplifying your side business idea income. Check out this extensive list by Justine Grey, covering the 59 Best Affiliate Programs for Business Bloggers to get some inspiration on how other bloggers are growing affiliate blogs from side business idea to full-time company.
Are you a professional in a field that can help answer questions for people looking for your expertise? Websites like JustAnswer and LivePerson match you up with people looking for answers to technical or professional questions. You can make money online by simply answering these questions and providing the right information to people based on their individualistic circumstances.
Note: There are dozens of other survey sites out there. These just happen to be the more well-known ones that have a reputation for paying out in a timely manner and not having impossible standards for cashing out. As always, be careful with your personal information. I recommend using an entirely separate email address for survey sites so they don’t clutter your inbox.