Even I was thinking on the same lines. Conduct a contest and pay the Winner. If you've good FB pages on the lines. Try it! It should work good. After paying up few bucks in 4-5 contests, the response will be immense there onwards. I haven't tried it yet. But this is the way that I'll be trying this.
Cool to hear, just be careful since when OgMobi doesn't have any mobile app offers they send the user to a survey offer. That might sway users away from you. Good luck!