Customized Facebook Application for Contests

Hello Freelancer, THIS PROJECT IS NOT ABOUT APP DEVELOPMENT, BUT ABOUT SOME CREATIVE IDEA FOR A CUSTOMIZED APP I have a facebook page on which i am planning to put up a store. I am already using ECWID, for the shopping cart app. It already has facebook like and share buttons for all the products that i would put up. I already have 1k+ likes (growing rapidly) and i post regular content which my audience enjoys. I want to run some contest on the page that people make optimum use of my page and the content on it. My products get promoted in these contests as well and my current likes promote my page through this contest. The price for the contests is much awaited, as its a part of the products that i am going to sell on it, and everyone on the page is already waiting for the store to go live. I thought of the FAN OF THE WEEK app, in which i can encourage people to like and share the content to highest extent to become the fan of the week and get the free gift. But still not sure about it. So i am seeking some idea, something fresh that can be used to fulfill my needs, which can be put up in a form of an custom app. Open to more creative ideas which could fulfill my needs. Budget is $10 - 20 max, however if i like your idea then we can discuss more and i can hire you for your services to make the app. I mean i would give a bigger project to you right away after discussing this. IN YOUR MESSAGE PLEASE GIVE DETAILED EXPLANATION OF WHAT YOU THINK COULD WORK OUT FOR THIS. Be Realistic with your bids. Happy Bidding