The music industry might not be as strong as it was in the 80s, but there are still plenty of ways to make money online as a musician. Sites like SoundBetter let you sell your services as a songwriter, producer, or session musician to thousands of customers a month. While Musicbed, Music Vine, Marmoset, and SongFreedom are perfect for licensing your music to TV shows, movies, and web series.

^{I’ve been doing surveys now for about 18 months, but when i first started i, just like yourself, carried out a lot of research about all the different survey sites and slowly but surely i discovered the best ones to join and now i’m receiving quite a good monthly income from them, but after saying that i am a member of a large number of survey companies and some days i receive that many emails that sometimes i find it hard to keep up with them all, but it is worth it as it’s started to pay off. I’ll not mention all the survey companies i’m with because there’s far too many, but some of the better one’s are Global Test Market, I-Say, Toluna, Mintvine, Your Word, My Survey, Swagbucks, etc, etc. What i do is i keep trying new ones all the time and then i keep the good ones and get rid of the not so good.}
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.
^{Fiverr is one of the biggest providers in the gig economy on the web and you can sell a wide variety of services and products through this medium. Do the research and find out what you can offer. However, keep in mind that like any other money-making task, it takes time to succeed here. And stellar reviews will help you generate more and more income over time.}
If you’ve got experience and expertise in a specific area of business, there are hundreds if not thousands of business owners who would love to jump on a phone call and pick your brain. This can be an easy way to make extra money online and to hone your skills to use in your consulting or freelance business. Sites like Clarity.fm let you create a profile where entrepreneurs and business owners can pre-pay to book a phone call with you for a set amount of time. Whether you’re an expert in raising money for startups, building apps, or running a restaurant, you can make extra money selling a few minutes of your time to people in need.
Domain name trading has been around for the last couple decades, and while most slam-dunk names have long been sold off, there’s still plenty of others that you can get your hands on for relatively cheap and broker as a way to make money online. Before you dive in, however, beware that some experts doubt the long-term viability of this idea for making money online. However, there’s always the chance you might just land on a lucrative domain name for a future billion-dollar company. To get you started, here are some tips from GoDaddy, arguably the world’s largest and most famous repository of domain names.
However, like anything else truly worthwhile, apps require a significant investment of your time or money upfront. If you don't have the skills, then you have to hire someone who can assist you in creating a great app. But first you need to come up with an idea that will sell. Do the proper market research and analytics to come up with the right app.
^{Of course, you have to be realistic. Just because some people make millions, doesn’t mean everybody will. But you’re not reading this post to become a millionaire, you are here because you want a free way to make some extra money and making YouTube videos is a great way to do it. Who knows, maybe your YouTube channel will one day become a huge and earn you hundreds of thousands of dollars.}
There are loads of resources for making money online as an affiliate. You could source products from ClickBank, Commission Junction, Rakuten Marketing, Share-a-Sale, Impact Radius and many others. Plus, many of the larger companies have their own affiliate programs as well. Do your due diligence and find the right company with a relevant product or service to your audience that you can sell as an affiliate.
Upwork: This website offers a great marketplace for selling just about any professional service. You don't need a merchant account, website of your own or anything else for that matter. All you need to do is be able to provide a high-quality service at a reasonable price. But be informed, you will have to compete with many others that are constantly bidding on open jobs. 
You can sell your ebooks through Amazon's Kindle program or Apple's iTunes Connect, which gives you access to a large majority of the digital-book reading market and the barriers for entry are incredibly low. You don't need to invest lots of money to make this happen, but you do need to invest lots of time, not only in writing the ebooks, but in marketing them as well.