Subscriptions
Each WhatsApp Business Account is subscribed separately. A subscription is what lets API keys for that account call the Messaging API — the console is not part of it.
No accounts connected
Connect a WhatsApp Business Account first — a subscription pays for one account, so there is nothing to subscribe to yet.
Meta's WhatsApp messaging and conversation charges are billed separately by Meta, directly to your own WhatsApp Business Account. They are not included in these prices.
Payments are handled by Razorpay, in a window it controls. Card and bank details never reach this console. Each account has its own mandate and its own monthly payment, and the month you have paid for is always yours — cancelling stops the next payment, not the one you have already made.