The cost of a BeRebel policy consists of two parts:
Monthly minimum
It's fixed, you pay it only once at the beginning of the month and it includes 200 km of travel.
It protects your vehicle even when you keep it stationary.
Cost per kilometer
It's variable, you pay it at the end of the month based on the km you've actually travelled (subtracting the 200 km already included, of course).
If your usage and driving style is fine that month, you'll also get a discount on this variable component.
Should you stop the insurance during the month, any kilometers included will be proportionate based on the duration of the contract itself.