Build a coupon cum comparison site in Wordpress

I want to create coupon sites in wordpress like these: [login to view URL] [login to view URL] [login to view URL] Basically these are sites that use the data feeds, API or csv files ( I am not sure how any of this is done) of major shopping sites like amazon, flipcart, snapdeal etc. and linking to them using their affiliate id's. They list all these shopping site links side by side so that visitors can compare prices. Clicking any link takes them directly to the shopping sites to make a purchase. There are readymade wordpress themes built especially for this. I can buy one of them so we can insert my affiliate links in them using these shopping sites API or csv files. We can start with 8 to 10 merchants but should be scalable to any number of shopping sites in various catagories in future. Important: I will want you to log into all my affiliate accounts and check how each site allowes us to import all their product details into our site and then implement the import. The site should be automatically updated as and when new items are added to these shopping sites. The site will be considered complete only when all links that point to the merchant sites have my affiliate ID's.