It depends on how what your goals are and how much time you put into it. In November, I was feeling annoyed that there was no easy way to see exactly what char

It depends on how what your goals are and how much time you put into it. In November, I was feeling annoyed that there was no easy way to see exactly what charge my phone's battery was at (at least none that were acceptable to me). I'd been curious about Android development, so I decided to "scratch my own itch". I spent 4 or 5 hours building a little app that would display my exact percentage in the tray at the top. Most of the time was spent tweaking the icon -- I'm not a graphic designer, but I eventually came up with something that looked good enough. I decided it would be worth the $25 fee to get a developer account and share it with the world. Programming is just a little hobby of mine, so while I've been using and loving open-source software for over a decade, I've contributed very little back to the community. So I figured if one or two people a day downloaded this little utility, I could feel good about myself. I put it online and went to bed. Eight hours later, over 700 people had downloaded it. Over the next couple of weeks, I got a lot of feature requests that I personally had no use for, and I'm a busy student, so I didn't think I had much time or energy to add a bunch of features I didn't need myself. But then my friend suggested I make a paid version of the app with the extra features. I thought that was a neat idea -- I figured that if I averaged one purchase a day, I could make $20 a month (Google takes 30%), which to me is a lot of money at this point in my life. It didn't take long before I was averaging 15 downloads a day. It stayed there for a while, until about month and a half ago, with no explanation I'm aware of, it jumped to averaging 50/day. I carefully and courteously respond to an average of 2-3 emails a day, and I release updates when I can find the time. But that's still not very much time put into this, and I'm making almost as much money as when I used to work full time. (I don't have a college degree and worked in retail.) The free version averages 1000 downloads a day.