In the field settings, set the Paid checkbox. Enter the price.
Then set the Price for each step checkbox.
Since that the specified price will be multiplied by the number of steps, i.e. the number of hours booked for hourly rentals.
For example: 'Monitor', $100 / day.
Let's check the results.
Book a coworking with two monitors for $100 / day for 3 days:
2 * 100 * 3 = $600.
See it in action.