To reduce shipping cost for your buyers eBay (and Kronocard) use what we are calling "Combine Shipping". For an order containing more than one card you don't want to charge X times the shipping cost it will make no sense right? If your base shipping cost to ship only one card is $1.99 you can charge an amount for each additional cards added to the same envelop. To setup this first you need to create profiles on eBay.
The link to the right page is: Manage shipping settings
On that page you need to click on Allow combined payments and shipping
Click on the Edit link to the right of the Flat shipping rule.
Now in that page you can select Add an amount for each additional item.
We suggest that you create a profile for each four types of cards in Kronocard (Standard, memorabilia, over-sized and graded) You can put any values for the combine. In that current case here if the buyer add multiple cards to the same invoice, each standard card will add $0.10 of shipping fees to the order.
When done you can go back into Kronocard.
Now in Kronocard select one or multiple cards to list on eBay and in the eBay panel on the left click on the Flat Domestic Shipping tab (1).
In that tab if you already have a base shipping entered, click on the refresh button (2) because you changed or created your combined profils.
It's now time to link each of the four type of cards to each of your eBay combined profiles by selecting the right one using the dropdown (3).
When done hit List/Modify Cards on eBay to list those cards with the newly created combine. All the next cards listed after this/those one will also get assigned the same profiles.