Corona SDK provides a simple but very powerful Lua based development system. Paired with your editor of choice Corona forms a complete environment to allow anyone to create their own apps that will run on Apple iOS (iPhone, iPod, iPad), Google Android, Kindle Fire, and Windows Phone devices.
The latest version now includes support for desktop (OSX and Windows) devices as well as Apple TV.
Corona is perfect for creating any kind of 2D games as well as business & educational apps using the included massive library of components and functions.
The community support provided on the developer forum is second to none with lot's of help and advice from both users and the Corona Labs dev team.
The recent acquisition of Corona by Perk means that the future of the SDK is in safe hands and Perk's Ad system coupled with the various store IAP modules means that it's easy for developers to make apps that can actually earn a decent income on the app store.
There are also lot's of free online tutorials and articles that help developers get up to speed quickly and easily as well as a number of very reasonably priced online courses at sides like Udemy.com.
I wanted to create my own mobile apps, using my development skills I have been able to release my own apps to the various app stores as well as being able to provide consultancy skills as a secondary source of income.