Here is a list of ways to make money online in Japan. If you are an ALT in Japan, you may have a lot of free time and you may want to make a little extra cash. There are some opportunities to make a little extra money offline as an ALT, generally through conversation lessons. However, if you want to make money online in Japan, here are some ideas.
Make money online in Japan
ALT's can make money online from Japan just by doing online surveys. One thing you might want to do is put your parents address in here and answer the questions based on your family home. That way you know no checks will be in the mail while you are flying home, and then when you do get home you get a nice fat check waiting for you!
Survey Savvy - Sign up to do surveys, get paid in cash for each survey! Open to internationals! Payout anytime!
After reviewing some online survey sites, ALT Wiki no longer recommends this method of making money online. These types of sites allow you to sign up but once you have signed up the surveys or other schemes are only available to people in America (and they can tell you are connected from Japan!).
There are some sites out in web-land that introduce student who want English lessons with teachers. Often they just get you to do it over Skype. Another way to make money online from Japan.
There are some places that will pay you for writing articles. They are usually require a sample article before they will publish you. Some places only hire you as a permanent writer, others on an article by article basis.
A friend recently started doing this. He found a new site looking for writers, he applied and showed his blog that was semi-related content and was offered the work. He's paid about ¥5,000 per article that get's past the editors and is published, max one per month.
Update: I asked how his writing was going and he said he gave up because the requirements were too vague. The terms were something along the lines of: "If you article is really great, we'll pay you this much, if it's OK, we'll pay you this much..." He also had to provide his own photos.
A different route to writing for other people is through places like UpWork or Freelancer. People post jobs and you bid on them. You have the chance for a little interaction and the hirer chooses the worker they like the best.
Another way to get paid for writing is the less direct route - marketing for other people, also known as affiliate selling. What you do is create your own blog with something like Wordpress. Using something like ClickBank, you can write articles and sell other people's products. With ClickBank you can actually get quite high percentage commissions, if you can make a sale.
Also, consider writing articles for this site! It doesn't pay (We are now paying for your writing!) so anything you can think of that would be helpful and/or interesting to other ALT's is what we want and is greatly appreciated.