The print provider’s flat shipping rates for each item are automatically pushed to your eBay store when it's connected with your Printify account. You can see all our shipping rates here.
However, there is also an added option to offer "Free shipping" for a product on your eBay account:
Please note: When using this option, you'll still need to pay for shipping in Printify. We recommend adding the shipping cost to your product retail price, so that it doesn't affect your profits.