Finances. You need to be good at quick math and be able to make quick decisions. You have to be careful how much you pay for a book, and then keep careful track of the expenses involved in selling it. For instance, when you sell on a website, they’ll take a commission from the sale. In addition, some sites, like eBay, will charge you a listing fee for each book. If you request that your money be deposited via PayPal, then you’ll be charged a transaction fee per book. If you’re not careful, the fees will quickly negate your profits.
Real estate is the obvious choice if you are going to make money on your money. I personally am not at the point where I can do any of this in a meaningful way BUT my parents are and they now own a couple homes outright and are collecting income from them to power their retirement income. It makes a lot more sense for anyone that has a chunk of cash sitting in the bank and are planning on slowly drawing from it because you technically still have all that money in a property (or multiple properties) and can sell them if you really need the lump sum of cash but you’ll earn great interest payments until you do that.

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 Upwork, which makes this a high-demand opportunity to make money online.

Did you know that English speakers are in high demand in Asia? As a result many are turning to freelance English teachers using websites like The site is basically a virtual online classroom for freelance teachers and students. Anyone can offer lessons (and set their own price), and anyone can take lessons. From a quick scan, it looks like making $15 to 20/hour is a fair expectation.
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 change 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.
I recently stumbled on the Trim app and I have to say, this one is a game changer. It’s a simple app that acts as your own personal financial manager. Once you link your bank to the app, Trim analyzes your spending, finds subscriptions you need to cancel, negotiates your Comcast bill, finds you better car insurance, and more. And of course, the app is free! My bet is that it will only take a few days for Trim to put an extra $100 in your pocket. So easy!