Online App for exchanging Amazon GC for cash payment

I need a small website that will allow people to enter their Amazon gift card number and receive a cash payment via paypal. The paypal payment does not need to be automated. The admin will send the paypal payment manually using the transaction details of each redemption. Admin needs to be able to control maximum Amazon gift card amount accepted, Amazon/Paypal payment rates (80% etc) depending on how much Amazon GC is currently in the account balance. There also needs to be a text field where the user can enter in their paypal email address. For example: Maximum Seeking: $1,500 Current Balance: Check before and after each transaction (Can be found on Amazon account page [login to view URL]) Rates: $0-700 : 80% payment $700-1000: 78% payment $1000-1300: 75% payment $1300-1500: 70% payment Over $1500: Amazon GC not accepted at this time If the rate tier would change from a large gift card redemption, then a combination of both rates would be applied equal to the proportion that the gift card amount in each tier. So if someone gave $1000 gift card and the current system balance is $0, then $700 would receive an 80% payment, and $300 would receive 78%. The system needs to be able to tell the user how much they will receive before they submit. After the gift card is applied to the system account and verified, the admin can retrieve information about all transactions. A spreadsheet of data that contains the transaction amount, unique transaction number (generated by system), rate of exchange, and paypal address. An email notification for each transaction would be best.