We charge monthly per active user in your Organization, pricing varies by plan. You can try out Powow Trial which is free for 3 months. Once you register with the Trial, your Organization will be automatically subscribed to the Essential Plan. You can upgrade your Trial at any time to Professional. If you want to upgrade to Enterprise please mail to firstname.lastname@example.org. Upgraded plans give wider access to Powow features. For more information check this link.