We have present site where this feature is working i cant expose name of our site in public but will tell people who we shortlist. In simple words we want users to vote on app like/dont-like, we want to refresh products what they like or dont every day from our server.
Once users give suggestion on those products we want app to send request back to our server and get latest promo-code and show that to user on screen. All data what user provide should be recorded in our database.
we need caching in this app as this should work when phone is offline and when phone go back online we do push alert to that user with promo code.
Even we want user to register on site or login if already member. We want to send push notifications to users on app for promotions and other things ( will talk in details )
feel free to ask questions.