You could still use C2, you'd just call the webpage within an iframe using one of the HTML plugins.
I'm sure you could theoretically build a shopping cart in C2, but you'd have to hook in a mail server and a database using PHP and MySQL; and there's hundreds of edge cases you'd have to consider: What if a customer wanted to change or amend delivery details? How would refunds work? Would the shop be restricted in certain areas? How would currency conversion occur? Every app store to my knowledge prohibits the sale of physical goods via IAP - you'd need a "real" payment processor such as Stripe or PayPal for it to work.
As these problems compound into a mighty one, and relying on a third part solution may be the easiest answer.
If you simply need a way of sending a message (such as text fields for an address form) - I'd look for email plugins (to my knowledge there aren't any - I know, I was surprised!). From a technical perspective you can send data from C2 to a web page with JSON, and from a webpage to an email with PHP; but I've never done this.