I have sold vintage items on Etsy and offered free shipping - as long as they are OK with waiting 7-10 business days for the ship. I can find a Scenario A ship in that time.
If the Etsy (or eBay, in your case) buyer doesn't want to wait - they can pay the normal rate. And maybe I can find a Scenario A ship that fast anyway!
Then I make $$$ - get paid to ship the vintage item I bought at an estate sale for $10 and sold for $50, offer free shipping, and then get paid to ship it.