Subscription fees are collected automatically for active devices on your account at the start of every billing period. This can be monthly, quarterly or yearly based on your selection.
You can cancel this subscription at any time to stop automatic renewal and also reactivate devices at a later date if needed. There are no "early termination fees", you can turn the device on and off as you need.
Subscription fees are all-inclusive: a single fee covers cloud data storage, app / portal access, SIM card data plan, support and API. You sign up to the data plan when you activate your device via the app or from the web-portal.
If you're looking to cancel your subscription, you can do so here.