There are quite a few major retailers who have free online shipping  (and returns, or item can be returned to nearest store). I can see why some consumers now come to expect that.. even overseas online stores.. have free shipping and free or low cost, e.g. $5 return (to a NSW address).

Consumers who are getting used to that (no extra shipping costs) and are going to go  if they see postage around $12-$15 for an item on ebay in Australia.

Another way the smaller seller can't compete with the big guys.

I have bought 3 items from an online store where the stock comes from the US..basically only paying for the item cost (same as on eBay) and no extra for shipping.