A Postage represents a single postage option attached to a Listing. If you do not plan to create different postage costs for different Listings, we recommend that when creating or updating Listings through the API, that you leave the postage field blank. This will result in your Listing being assigned your default postage costs and options, which can be set from the Members Area > Selling > Seller Tools > Default Listing Settings page.
Combined Shipping: On Hip eCommerce, when an item is purchased, the cost to ship the item is represented by the price in the Postage resource. If a buyer purchases multiple items from a Seller in a single Sale (Order), the highest price for any of the applicable Postage resources will be used for the attached Listing. All other Listings will be charged the price_addl rate instead (the cost to ship the item as an additional item in a Sale (Order)). If there is a specific item which you do not wish to offer combined shipping on, simply set the price and price_addl to the same rate. However, please keep in mind that Hip eCommerce requires all shipping settings to be reasonable and not excessive.
Table Rate Shipping per Number of Items: The price_addl field can be used to set-up table rate shipping per number of items in a Sale (Order). For example, 3.00/5 where 3.00 would only be added after every 5th additional item in the Sale (Order).
