If you want to help shape digital products in their early stages, joining an online focus group or answering survey questions is a great way to make extra money online. They don’t pay as much as some of the other options we’ve highlighted, but you can join groups on sites like Survey Junkie, Swagbucks, and IPSOS that pay out through Amazon gift cards, check, or PayPal. You’ll be asked to provide a bit of information about your demographics (age, location, etc…), but after that you can get going making money through surveys.
Prior to that group, they had an online community for teachers looking for lesson plans. That probably sounds pretty random, but it's crazy the type of communities you can build and rally people around. If it's something that you're passionate about yourself and you want to connect with others that have that same passion, then an online community is something you should definitely consider.

Job well done, Satrap. The first thing I look for in a site like this are signs that the author is being paid to hype the companies. It’s very tough to find good information that isn’t stricken with bias. There were a couple of times during the article where I actually got excited thinking, ‘Hey, I could do that. I’d actually LOVE to do that.” That being said, I can’t help noticing that you refer to all of it as “extra” or “supplemental”income. Are you saying that with all of these options, sticking to one’s regular “day job” is required? In your experience, if someone really commits to doing this, is it possible to earn a decent living? Cubicles suck.
As long as there is still the written word, there will always be editors. Freelance editing and proofreading not only pays a decent hourly wage, it also gives you the chance to read about potentially interesting topics too. What's more, pursuing freelance writing & editing as a business idea can afford you a lifestyle that lets you travel the world as a digital nomad. You can find lots of job postings from companies and individuals in need of writing, proofreading, and editing services on Contena, which makes this a high-demand opportunity to make money online.

2. InboxDollars – InboxDollars is similar to Swagbucks, since you’re going to be taking surveys, shopping, etc., so if you want to maximize your return, sign up with both websites. They also offer a search engine that pays you (like Swagbucks) and you get $5 just for signing up.  I won’t continue to list survey sites one after another down the list, but if you want to get paid to take surveys, also check out GlobalTestMarket, E-Poll Surveys and Survey Club.

It doesn’t pay much, but if you’re a healthy person and want to make a bit of extra money online, the AchieveMint app will reward you for doing things like walking, tracking your food, or taking health surveys. AchieveMint works by connecting to fitness apps you might already be using like Fitbit, RunKeeper, Healthkit, and MyFitnessPal and then giving you points for certain actions. For every 10,000 points, you earn $10 with no limit on your earnings. 
×