Day Spa marketing website

We are a Day Spa Marketing company that sells day spa packages. We do have 2 small websites already established, however, we need work done on one of them for now and maybe both down the road. The site we need work done on is a small site that allows people to log on and pay and then print out a day spa certificate. The certificate has over $500 of day spa services and we sell it for only $49.00! We do have basic paypal set up already. We need someone to set up the website to do a couple different things. First we need to set up a way for them to enter a COUPON CODE to get the card for just $49.00 compared to the normal $78.00 price. Most importantly, we need a way for them to be able to use (6) different coupon codes. Each code represents a different sales representative. We need to be able to keep track of who was responsible for bringing that customer to our website and someone to set that up. We also need you to set up the pay and print capability. So that it wont print the $500.00 Day Spa Certificate until the correct coupon code is entered and the payment has been confirmed.