CiviCRM Spark trial and pricing?
Looks an interesting service and will suit many and certainly a good way of getting started. I can't see a contact email for the service or a list of the extensions included. I think I've probably already grown beyond this service as I am using a few extensions, but had it been there when I started, it would probably have been quicker that getting it going on another hosting provider.

But to answer you question - it does look to be monthly - see the T&amp;Cs linked from the signup page (direct link https://civicrm.org/spark-terms-and-conditions).