That's a good question. I guess the answer depends on if you can find enough underserved niche markets that you know enough about to create something unique and special.

And remember, that $10k was in 6 months. So potentially, we're talking about $20k/yr for this app. 10 apps would be a potential $200k a year.

Right now, I'm content with this being supplementary income, but I never imagined that when I paid that $99 developer fee that I'd do so well.