Yes. Every plan accepts your own model key. On Pro, Max and Team, you choose whether the agent uses your key or the plan's included model usage. Requests made with your own key are billed by your provider and do not count against your plan's limits.
That makes a paid plan worth it for the features alone: all platform connections, the full template library with updates, shared dashboards and GitHub checks. On Enterprise, admins can set one organization key for every member.
Plans and prices are planned, not final, and nothing is for sale yet. Compare them on the pricing page, or read about how usage limits work.