If you are not going to run a payment gateway, you will have to make modifications to store information about each of the orders that someone places. If you have DataAssist, you can use that to store the information into a database. Or if you have eCart there is a store cart details in database server behavior. If you have Universal Email you can use that to send an email with the products listed in the email.
In addition you will have to remove the shipping and payment gateway code.