I would strongly recommend that you do not send any billing details like credit card info via email, it is not secure and can be illegal in many circumstances.
If you would just like to gather some details from the user instead of send them to a checkout you could have a page with a form on it that the user fills in, then you can apply Universal Email to the page to have the info sent to you. You would just need to craft the message body and use the bindings for the form to get the values in the email.
On your cart page you would just adjust the checkout server behavior to go to this new page you have created.