573109 Facebook app for website

Hi, I have a small ecom website where people can buy and sell coupons. I want to take it to facebook. 1. Can the website be created as facebook app and can it be operated from facebook without coming to site url. 2. Can I create a app on clicking which people are redirected to my website. If yes, can I post that app inside my facebook page (normal page)? Please let me know the options and the costs involved. Would be happy to talk to competent people.