Diving into the new (new? well depends on you) Android Gradle build system may be a scary experience when you are used to the good old Eclipse ADT environment.
But really, the Android Gradle system is worth it, it has SO MUCH to give you!

The problem is to find some examples to get started, as Android Gradle is still quite new.

Samples exist

The documentation is not perfect yet and you may think that there is a lack of examples/samples on Ze Internet.
So if you haven’t found what you want on the the Android Gradle Plugin User guide, maybe it worth having a look at the bottom of the New build system page, where some samples are available in Zip files.

Another good resource is the Git repo of the build system, in the tests folder you will find plenty of Android gradle build examples, which are actually gathered in the archives available at the bottom of the New build system page, previously cited.