This project should take at least 15-20 days to code and another 10 days to test properly before you release it in the market. My understanding:
1. Transfer of cash reward (on installation) to bank account/UPI wallet
2. Cash reward for purchasing product (product deep-links will be sent to the app) made available through DEALS
3. A task-bucket to be set in the app. The user will get reminders/notifications (email, Google calendar or Push notification)
4. Expense Manager for the user where he/she can add expenses. Total expenses will be sent to the user through an email at the end of the month (at 12 Midnight).
Question: Besides the manual expense entry option, do you want a capability to read SMS received by the user? Similar expense management apps actually read SMS to collect expense information.
5. Integrate Bharat Bill Pay API for bill payments, mobile recharge etc. User can use the earnings to make the payment. An additional payment for bill-pay should be added to the user’s account through a payment gateway (like PayTM or PhonePe)
6. Refer and earn option using a referral code. The referring person will get 10% (the figure should be manageable by the admin) along with a fixed amount.
From your clients, you will get URLs of products/services/deals etc. with unique tracking code and you will use Offer18 affiliate marketing platform to manage this.
Let me know if I understood your project. Me and my team can do this.