Has anyone had luck with Facebook mobile advertising for your app?

[Alittletf]

Currently we are looking into advertising on Facebook to boost downloads/sales. We first looked into advertising for our fan page which worked ok until we learned of the expensive pricing to promote a post to all your "likers."

Now we are looking into ads on mobile facebook that allow the user to download the game straight from their phone.

Has anyone had any luck with this? Its not cheap.