Write some Software Tool to record user purchases

I am looking for small web based tool to perform following Actions : User Mode -Register a user -Login Purchases by user -Calculate Cashback Amount earned by user - user can request for Cash Back Amount in different option (e.g. BanK Transfer, Gift Voucher, Shopping Voucher) -View Purchase Register -View his Ledger i.e Purchase and Cash Back received and balance amount Admin Mode : -Register Shops & category and Offered Cashback % or fix amount -Approval of Purchase made by user - View different reports and queries (e.g. User Ledger, User Purchases, Payments ) - Process the Payment i.e. bank Transfer, Gift Cheque, Shopping Vouchers) Need to send email notification, when user is registered, submit his purchase, Approval of Purchase, Process of Payment