Yes, CanIRank offers a Free Preview plan so you can test out the software without having to put down a credit card.
You can stay on the Free plan for as long as you like, but you're limited in how many reports you can create, and how much data is included in those reports. If you like what you see, you can upgrade at any time to lift the restrictions.
You can select the Free Preview plan when you first sign up for CanIRank:
Or at any time from the plan selection page: