ASP.NET站点会员费处理

I am building a site where people will sign up and pay to use an online web app (a yearly fee). What I've been looking for, but can't seem to find is a very simple checkout/order processing component for this type of scenario. I really don't want or need a full-blown shopping cart with product pages, etc., since we're really only selling one product. Just need to be able to have a simple checkout page to confirm they want the subscription and enter a coupon code (optional), and then provide a variety of payment options. Initially I only really need PayPal Web Payments Standard integration, but would like if it already has hooks for others like Authorize.NET in case we add that in future.I am building a site where people will sign up