Does step have a monthly fee?

Excuse me, I was wondering if I could get some clarification on the pricing structure for Step. Specifically, does Step charge a monthly fee for its services? I'd like to ensure that I'm fully aware of all the costs associated with using the platform before I make a decision to sign up. Is there a flat monthly rate, or does the fee vary based on usage or other factors? Any information you can provide would be greatly appreciated.