"We will begin billing your Payment Method for monthly membership fees at the end of the free trial period of your membership unless you cancel prior to the end of the free trial period". I guess I will not sign up.
That gives you free "5 minute rentals", which are designed to let you decide if you want to actually rent a given article. If you decide to rent some articles, and so need to pay for that, you'll then have to give payment information, of course.
The rentals are for 30 days, and are sold in packs of 5 rentals for $20. Yes, free would be better, but compared to the alternative of paying $20-40 per article to buy single article access from major journals, DeepDyve looks like a great bargain for the researcher who does not have access to a university library.