I expect you realise this, it's not apparent from your post: Coupon and group buying sites have been a thing almost as long as the Internet has. I'd be amazed

I expect you realise this, it's not apparent from your post: Coupon and group buying sites have been a thing almost as long as the Internet has. I'd be amazed if any of your long standing competitors are anywhere close to the billion dollar mark. So I'd expect you to define your idea by what you intend to do differently than all those others who went down that same path. Not that that's a barrier to success by any means.