I tried to spend time on business ideas today, but after poking around the Jira app store, I stopped. On one hand, it was nice to see that developers were able to charge prices like $20/month for their apps. On the other, I really hate Jira and have a hard time imagining myself making apps for it. But I shouldn't dismiss it out of hand.
The other way that people actually make money by selling software to people (according to word on the street) is Shopify apps. I created an account there and was going to try to get a feel for how the platform works, but then they ended my free trial. Again, I have a hard time believing that I'd make an app for something so foreign to me, but I have limited choices, so I should probably pay for an account and give it another go.