There’s an excellent chance that you have one or several musical instruments sitting in storage that haven’t been used in years. Perhaps it’s a leftover from when you were in school, or even from your days playing in a band. Whatever the reason that you have it, it’s probably worth money if you can sell it. Brand-new instruments are ridiculously expensive, so people often look to buy used equipment instead, particularly if they are novices.
If writing books interests you, an option you have is to self-publish eBooks and paperbacks with Kindle Direct Publishing, and reach millions of readers on Amazon. Publishing takes less than 5 minutes and your book appears on Kindle stores worldwide within 24-48 hours. One can earn up to 70 percent royalty on sales to customers in the US, Canada, UK, Germany, India, France, Italy, Spain, Japan, Brazil, Mexico, Australia, and so on. One can keep control of one's rights and set their own list prices and also make changes to one's books at any time. BooksFundr and Pblishing.com are two other places to get your book published and earn money.
17. Amazon – Have you heard of FBA? It stands for “Fulfilled by Amazon” and it’s getting pretty popular. Basically, you buy products (in bulk is best) and ship them to Amazon for them to store. When your products sell, Amazon packs them up, ships them out and sends you the money (after taking their cut). There are people making a full-time living from FBA, while others just do it for some extra money.
Find a profitable niche: We’ve talked about this a lot. But, where are you most comfortable. What niche do your skills, values, and interests intersect? Do you have 10 years of experience as a technical writer? Do you have long-standing PR relationships that’ll be invaluable in helping startups launch a successful crowdfunding campaign? Determine what makes your value unique, and lean heavily on showcasing that strength to your potential clients.
Find a profitable niche. Starting with your interests, write down as many niche ideas as you can. Think about topics people might search online. Ideas include passions (like surfing or body building), fears (like spiders or speaking in front of crowds) and problems (like getting out of debt). Do keyword research to see it others are interested in the topic. Find out if a domain name is available that matches the keyword 100 percent. 
Dating sites and apps are extremely popular and have become more and more niche as the industry develops. They can also be very profitable, as there are many ways to monetize them. You can charge a joining fee, provide premium subscriptions, or make money from advertising on your site. White Label Dating provides a pre-built dating platform for your project. You simply choose the niche and branding for your new dating site. Once your website goes live, you just need to promote it, manage the users, and collect the earnings.
Tools & Resources: I’ve written a pretty comprehensive guide on the best web design software that covers both free and premium software packages. If you’re serious about becoming a web designer, then I recommend purchasing the full Adobe Creative Cloud Suite. At $49.99 per month, this is probably a bargain considering what you can achieve with this set of tools.
Here’s a good example of how lead sales can work in real life: My second website, Life Insurance by Jeff, brings in a ton of traffic from people who are searching the web to find answers to life insurance questions. While I used to have the website set up so I could sell these people life insurance myself, it was a lot of work to process all the different requests and clients. As a result, I started selling the leads I gathered instead.