[Avalaxy]

I'd take a look at Xamarin and/or Xamarin Forms. It's really good and allows you to build native apps for iOS, Android an Windows Phone with just 1 codebase. It can save tons of money.

Xamarin Forms is taking it all a bit further than the other Xamarin offers because Forms even allows you to build 1 UI using generic concepts that will be rendered in the style of the platform that's running the code. I have to warn you though: Forms is still pretty new and buggy. The concept is really really good and it does work pretty well, but it's just not mature enough for big applications.