Develop App like TaskBucks or Cashout with few changes

would like to build app like cashout, watch4dollar which is rewards app for seeing videos or surveys,with FIREBASE backend and able to include any type of SDK . Budget is not more than $200. either in flutter preferably hybrid API will be provided UX/UI everything is from your end. well this is for our screening type of app once you are in you will awarded more projects Here is the demo apps: [login to view URL] [login to view URL] [login to view URL] or [login to view URL] or [login to view URL] Developer Will - Build Mobile App - Build Web Services - Construct Simple Backend that will manager users, edit profiles, points and notify us of pending payouts ** Priority given to those who have built similar apps, or have source code/snippets to accelerate the process. This app is essentially the following: 1. User Registers using email or social network 2. User completes various offers using offerwalls (CPALead,Adscendmedia,AdworkMedia) 3. When user completes offer advertiser posts to postback script that updates users points.(Very important) [login to view URL] user refers to his/her whatsapp friends ,user gets 5 points per referral 4. User can see his stats and points and when they reach 100 points they can request a paypal payment 5. App notifies admin to send money