Facebook Application - simple shopping cart with check out to sell one product

I need a simple application developed for Facebook.. to SELL custom documents which will be delivered within 24 to 36 hours. These are digital, files delivered electronically so there is no shipping etc. Users can pay per page and then download the document they ordered after the given time, or it can be sent to them within the Facebook application itself. Delivery options are open to you and your developers suggestions are welcome. IMPORTANT: USERS SHOULD BE ABLE TO SEE A SMALL BOX (AFTER INSTALLING THE APPLICATION ON THEIR PROFILE) SHOWING 2 PARAMETERS: DELIVERY TIME AND NUMBER OF ITEMS. UPON CLICKING NEXT THEY SHOULD BE ABLE TO ENTER A FEW DETAILS AND PLACE ORDER IMMEDIATELY VIA PAYPAL. THEY MUST NOT HAVE TO LEAVE FB, IN ORDER TO COMPLETE THE TRANSACTION. THIS IS VERY IMPORTANT. Orders will be stored in a simple MS Access file, based on delivery time chosen by the customer. Most importantly it should have a Paypal "Buy Now" button .. user can simply enter the number of pages required, details, and click pay. Please get back to me asap.. with a reasonable price quote. I would like to have more apps developed in the future.