Pro Sites - Credit Card - Free Trail


Is it possible to offer a free trail with Pro Sites without collecting payment details first. I would like users to sign up and then get notified that their trail is running out at some point and only then add payment details if they wish to continue. I do not find the option to create this environment. Also when offering only a monthly option there is no mention of the free trail on the checkout page. It would be ideal if users could sign up without payment details and if they could be taken directly to a sign up form, from a button or link. Your reply appreciated.