When you choose a paid plan, you pay at checkout using MTN Mobile Money, Airtel Money, or a Visa card.
It is quick. Pick your plan, go to checkout, choose how you want to pay, and follow the prompt. If you pay by mobile money, a message pops up on your phone asking you to approve the payment, and once you do, you are done.
There is no automatic charging. You pay for a set period, and when it is coming to an end, you simply renew if you want to carry on. Nothing is ever taken from your account without you starting it yourself.