Copilot Studio is available on a Pay-As-You-Go basis from 1 December, 2024. That means that you can now choose to buy either the original Capacity Pack of 25,000 messages for $200 a month, or pay for messages that you use at a cost of $0.01 per message. As you might expect, messages are paid for via an Azure Subscription at the end of the month. If you want to, you can combine the two options, with the messages from the Capacity Packs being consumed first.

Find the Microsoft announcement here: https://bit.ly/4fgt7J1, and the pricing page here: https://bit.ly/4gvpLTs.