Deal shopping

Hi geeks, I m looking for a script like ( [login to view URL];utm_source=crm ) but with few modifications. This link is just to give you an idea. Lets keep this script as a base. What i want in this is 1. When a seller adds a product than at the place of discount field I want Offer: Buy : dropdown menu (1-10) Get : dropdown menu (1-10) Offer description (text box) at the place of discount description This field will be mandatory for the seller as my site is exclusively an offers and deal site 2. Category listing structure should be like this 1. Buy one get one main catgegory sub category 2. Buy two get one main category subcategory and so on ... So when a seller will add a product when he slects category say electronics and subcategory digital camera and in offer he selects buy one get one than this product should be added under buyonegetone -> Electronics -> Digital camera Also I need commision system. For an example if one of our seller sell products worth 10000 INR Than he will need to pay us our commision which can be set up as per the negotiation with different sellers. Rest we can discuss more later on reagrding small tit bit chanages.