When you subscribe to the price plan in Bokio, you pay by card and can choose whether you want the payments to be made monthly or annually. To see your upcoming payment, go to Settings → Billing of Bokio services.
There is no lock-in period on the price plan. There is also no notice period, but you always pay for the current month after you have terminated your membership.
You cancel your subscription by downgrading the price plan. You can do this at any time. You then keep your current plan for the period and pay for the entire period, after which the subscription changes to the new plan you have chosen.