This field allows you to edit the text that shows your total price per delivery (for prepaid plans) which is displayed on your product page. By default the price will be shown as the simple currency amount followed by /delivery. Typically this field should stay as the default {{prepaidPerDeliveryPrice}}/delivery.
If you would like to customize this field, an example of how you might do so would be inputting the following text Only {{prepaidPerDeliveryPrice}}/delivery! then your customers will see the price as is highlighted below.