You can actually make and sell shirt designs about coding, like this one I created teespring.com/electronics-dont-love-you-back or this one I also created teespring.com/270-percent the links are with big discounts. This site enables maximum 10$ profit per sold shirt which costs 20$. Of course then you need to somehow get people to see them to buy them, but if you have some websites I guess you will not have this problem.

So the sites are teespring.com for selling entire shirt designs and spreadshirt.co.uk for selling only the image for the shirt, at around 5$.

One approach that's worked well for me is by doing video courses. There are different ways you can tackle this, but essentially you can create a few JavaScript courses and continuously sell them throughout the year or until they become outdated.

Websites like Teachable can help you host your own courses. Self hosting is a little more work but you keep what you make. training.talkpython.fm is a good example of a self hosted training site. There are also places like egghead.io, Pluralsight, Lynda.com, etc that will do the hosting and marketing for you. With those sites, you'll end up getting a percentage based on their respective formula.

So for me, I'll do my regular work during the day and record video courses at night at home when everyone is sleeping and I can get some quiet. I had to purchase a microphone and some recording software (e.g Camtasia), but that was all of my out of pocket expenses.

You can always do what I do and ask your parents for cash.

I'm assuming by passive income you mean revenue that's generated from investing work and kicking back to profit. In that case -- it's all about creating products.

You could try selling books about Javascript, templates/plugins, or creating profitable apps and services. Get into affiliate marketing and advertise software with your coupon code (or just use Amazon and pimp your hardware setup). Write Medium blog posts behind their paywall. Install a questionable bitcoin mining plugin on a popular website you create. Write patented software that you can license to companies.

There's a myriad of profit models you can pursue, it's simply what you're willing to invest time and work into.

Ask yourself, what do people need and how can I provide that solution? And preferably, how can I provide a solution that works for itself (i.e; doesn't require any input).

The one thing to keep in mind is that there's really no such thing as "passive income". Unless you're someone in Hollywood making residuals off a movie, or getting checks from an old court case -- it takes consistent work to create persistent revenue. Products don't sell themselves.

I have been facinated by this for a long time and must conclude, there's not really something like passive income. If you think about it for a moment, all the blogs about passive income, they spent huge amount of time bragging how little they do, because what they do is to sell you a dream about a easy life.

But there's something you can call independent income, which allows you to move freely, work when you want and scale as you like or need to. It will still require a lot of work, nothing comes for free (almost). You would have to do things like accounting too and there's a greater risk than a regular job.

If you can manage it, I can say honestly it's a great way of living.

I don't have the equipment to mine cryptocurrencies, but that would be one way.

What I do is contributing to open source, and have a liberapay account (I used to use gratipay, but it's closed now). If you are in a good project with generous users, this can give you a few extra dollars.

youtube.com/watch

This gives some good ideas. Might not really be passive though so you could create an app with a subscription pricing model or mining rig? :P