How to display a float with two decimal places?

I have the following configuration in my domain.yml: price: type: float min_value: 0.0 max_value: 10000.0 initial_value: 720.0 mappings: - type: custom

I want to make rasa always use two decimal places. e.g. 10.10 or 10,23, so that I get an Output like: “Hello User Name! Do you think $10.10 is a good price?” How do I configure that?