Smoobu provides a 14 day free trial period, all features included. During your trial you have access to all the Professional features, as you would on the paid plan. To sign up for a trial there is no credit card required and no obligation to purchase after trial runs out.
Unfortunately it is not possible to extend or postpone the trial, but you can definitely subscribe to a monthly plan until you feel confident enough to change to the yearly one. You can cancel it any time - hopefully you'll stay with us! :)