Workflows allow for extremely flexible cost calculations, which can be based on information held at resource or project level, or based on custom tables defined by the facility.
A simple example would use cost information held at Resource level, and core hours defined in the Global Parameters to allow the facility to charge more for a piece of equipment during the hours when it is most in demand.
A workflow like this would be triggered when a new booking is made, or the start or end time of an existing booking is updated. It would calculate how many minutes of the booking fall into the defined peak and off-peak times for the facility. It would then use the peak and off-peak rates defined elsewhere for the Resource to calculate a total cost, which is stored on the booking.