The core recurring modules provides for a trial period. Basically, you can just set the product price to $0.00 and then set the recurring fee to whatever you want it to be. Just don't bill the first fee until 7 days after the order is completed.
This modules works best in conjunction w/ some other credit card processing module, but there aren't a lot of payment modules w/ the recurring handler integrated yet.



Joined: 08/07/2007