A couple years ago I built an app for my wife and I to keep track of allowance. As a way to save money, any non-essentials that we want to purchase are recorded as allowance, and we get a limited amount of allowance each month. As a bonus, we can each set a daily task that will give us a little extra if completed.
The app was built with Ruby on Rails as part of what I called my “omni” app. I used this app for a lot of things over the years, but eventually decided that this allowance module and another note-taking module were the only ones I used consistently. So when it came time to upgrade to Rails 5, I decided just to include these two modules.
I’ve been thinking about whether I could distribute and/or monetize this piece of the application. I think it would be hard to compete with Mint and other banking apps. Setting up a kind of multi-tenant structure is a bit outside the scope of my knowledge, but there are some services that would be able to take care of that for me if I were able to make enough money from it to offset the cost. It would need some serious modifications to be distributed, also. I imagine the target audience would be families with children, which would require a bit more access control than is currently in place.