Add coupon page for paypal site

Here is the site that needs the coupons - [login to view URL] The above site must have an intermediate page after an item is selected. Here is what it needs to mimic - [login to view URL] The promo code is not for everyone so I would like the promo code to be on the page of the shopping cart, not before it. Should be one discount for the total order depending on the code they put in which will make the % discount different. For example, for code word "Gift" is 15% and for "Special" is 20%. I need to be able to generate the code and discount amount easily. Here's how it should work: 1. consumer clicks on a product they want to buy and takes them to the "Your Shopping Cart" page, which will show the original price. 2. The promotional code box should be located on that page and the consumer is allowed to enter a code. Once they do they will click update or promo code (whatever we decide to call it) and the new price will appear. It is important that this is done within 48 hours after you are selected! Do not bid if you can't do it. I reserve the right to deduct $10/day if you don't finish in time. No escrow until I see very good progress.