There are many rules other than the simple price list to cater for your every billing need, a description of each and an example is included below:
To add a new rule, you will need to be in the billing rules page.
Go to the Admin Section from the start page and Click Billing Rules
Expand the company to where the rule will live and click New Rule
Note: The rule can be added to a folder. By adding a \ within the name, any text before the name will be the folder. This allows you to group your rules.