If you often sell the same (say single lose Model Cars in 1/64 Scale or Hasbro Black Series Star Wars figures) you should set up Shipping Groups to make listing much faster.  Here is how to do this  -

1. Navigate to your Seller Dashboard and click on Shipping Groups 

2. Click on Add New Shipping Group 

3. Add all the details such as the Group Name, the Zone, the Cost, and the Cost to ship with another item. Here's an example for Hard Rock Cafe Pins -

NOTE:  "Cost in $ to ship with another item" is essentially rewarding buyers that buy multiple items from you at one time, which increases your sales! So using the screenshot above as an example, let's say a buyer bought three different Hard Rock Cafe Pins from you, the shipping cost would only be $7.00 plus $1.00 plus $1.00, for a total of $9.00 for shipping.

To edit your Shipping Groups click on the little pencil icon next to the Group title and to delete, click on the little red trashcan icon  -

Once you edit a Shipping Group, you can apply the changes to every item that is already within that group.