Build up a following on your Instagram account and you could quickly be approached by major brands, gear companies, and other relevant businesses that sell products or services related to the type of content you share on Instagram—creating multiple potential side business ideas that'll come to you. If you have the right marketing skills and hundreds of thousands of followers, you can easily charge anywhere between $500 to $5,000 per post (or more)—which makes for a very profitable side business idea. Check out this fashion Instagrammer on ThePennyHoarder, making a significant income from brand sponsorships. Once you get some traction, to cut down on the amount of time you spend uploading images, you can make your entire workflow more efficient by posting photos from your Mac or PC.
Tutoring pays quite well, and many clients will refer you to others, especially if their son or daughter shows significant improvement or finishes a class with a good grade. People want to know what they are paying for, so advertise your skills by having previous clients give testimonials and providing information on your own educational background.
However, it is when I tried to get some hard info out of it that I ran into trouble. For example, the one website that was recommended for doing little IT jobs on the side turned out to be a depressing place where people desperately bid for jobs for extremely little money ("$12 if you configure my email software"). Also, the tax chapter didn't seem to really belong: I had to read it multiple times and still couldn't figure out whether I'd have to pay self- employment tax as a day trader or be subject to schedule C, etc...
So you love to cook? You could start a restaurant that will take a full-time commitment and a lot of money – or you could start a weekend catering business or a mobile food truck. A business where you provide small services on your own schedule can grow as much or as little as your time allows. Look for those opportunities while you're starting out.
One huge driver of these price increases, of course, is the growth of WordPress and as building websites have gotten easier, more people have been willing to shell out pretty big bucks to get the exact domain they want. I currently own over 800 domains and a vast majority of them have a “Domain For Sale” landing page where visitors can submit an offer to me. I have them all set-up so unless an offer is over $1,000 then I don’t receive the email. So I don’t have to deal with lowballers.
If you have a way with words and know how to make the keyword-friendly, beautifully designed, SEO-optimized landing pages, why not charge other companies for your services and turn it into a money-making side business idea? Even a short landing page is worth a couple hundred bucks in most cases, and so much more if you know how to pitch your prospects well. If you want to get started with your business idea of becoming a landing page specialist or freelance copywriter, check out Len Smith and Sean Kaye's awesome course on Udemy, Copywriting Secrets: How to Write Copy That Sells.
It’s not on this list but Brand Ambassador/Promo work is another very flexible, fun, and lucrative side hustle! Basically you promote your favorite brands at awesome events (e.g. handing out Red Bull or demoing new products at high foot traffic areas). I created an entire resource website on how to succeed in this industry called “Brand Ambassador World”. It has everything from resume designs, to super helpful tips and tricks, to where to find promo gigs, to a comprehensive list of agencies, etc.