If you need more workspaces than your plan includes, you can add them one at a time for a monthly fee each. The price is in Plans, credits and prices.
What you get
A workspace with its own My Brand, voice, Watchlists, Routines, weekly brief, chats and Collections. Fully separate from your others.
Credits are not separate. They belong to the account, so an extra workspace gives you somewhere else to work rather than more allowance to work with. Budget for both if you are taking on a client.
Adding one
New workspace in the sidebar, or Settings, then Workspaces. You name it, confirm the charge, and go through a short brand setup.
Do the brand setup properly before working in it. A client workspace with an empty brand writes generically, and that is more visible on client work than on your own.
Removing one
Delete it in Settings, then Workspaces. The charge stops, and everything in that workspace goes with it permanently.
If a client relationship might resume, it is worth exporting anything you want to keep first.
When you do not need one
One brand across several platforms is one workspace. Platforms are handles inside My Brand, not separate workspaces.
A one-off project is not a workspace either. Use a Collection and a few chats.
Reach for a workspace when the brand and voice are genuinely different, because that separation is what a workspace is for.