how to create a single subscription with $0 price

I would like to create a single subscription for my website. So all users that will register will fall to the "Members" subscription/level. And I want that upon registration it will ask the user for billing information that is stored on my Authorize.net account for future billing purposes for each customer.

I am able to create a subscription and tested the default register page. After entering basic info it successfully created the account without even asking for billing info like credit card info. please help