What happens if I am not satisfied with my Confluence purchase?

Whilst im sure you will like Confluence in the rare case you don't want to use it then simply cancel your monthly cloud subscription. For annual or one off payments I don't believe they refund the balance, so Monthly cloud subscription is your best bet. If you have any doubts try the free 30 day trial before going in large, or limit to a focus group of 10 users for $10 a month before rolling out at scale.