To get there, please follow these directions:
​Customize > Products and Services > Pricing Rates

Pricing Rates are only available for Rental Products, they allow you to increase your base rate by a multiple. The Pricing Rate name can be displayed on your invoice beneath the product if enabled. These are initially only applied by your product categories but you can choose to override individual products by a fixed dollar amount.

The Red arrow will bring you to create a new rate and the Blue will edit an existing rate. 

When you are first creating your rate, add in a name, description, and increase multiple. If you would like you can turn on "Cent Rounding" to have the increase round to the nearest value that is chosen. If you toggle off "apply to all categories" you will be able to select categories and also search for individual products.

After you save your pricing rate, a new option will appear to view the products included on the rate. 

When you "View List" it will let you delete products from the rate and also give a fixed dollar increase instead of using the multiple already chosen. 

When you are in the Cart of an order, that is where you apply it to the products individually! 

Or you can select it to apply to all products in your order.