With credits you can add extra functionality to PlanManager.
This allows you, for example, to conduct surveys with your customers, send SMS, place digital orders with component suppliers, monthly contribution for the apps, ...
You can purchase these credits via System-> Credits:
1 credit costs 1 £ . Enter the desired amount and then click on "Buy a new bundle"
You can also see your remaining balance of credits in that overview:
In the same overview you can see on what the credits were spent on: