Dynamic Mobile Shopping application

I want to have a working prototype (with only a basic GUI - see below) of an application that can search for the lowest prices on various online selling sites (eBay, shopbot, amazon, etc). Once a certain price is reached for each item, based on the users input (i.e., selecting the price they want to pay for an item), this creates an alert to the application and the customer can purchase the item at that price plus a transaction fee (or compulsory viewing of an ad). The application must include the following: - 2 versions: 1 free with ads (through AdMob) and one paid for through yearly subscription or transaction fee - Link to payments through credit card, paypal, mobile application subscriptions - An easy online search of online stores which sell the item (rephrase?) - Email alerts to the user - Application alerts to the user Basic GUI includes the following: - Square place-holders to represent buttons or user input buttons - Use of number scroll to change digits Platform: Prototype on iOS Future port to other OS's keep in mind or created simultaneously (Preferred) Stage of Development (can be discussed) 1st - Mobile app that searches online stores and detects prices 2nd - Method of completing transactions using paypal through the app 3rd - Email and application alerts for the mobile app 4th - Link to social media (post, share, send items to one another)