@feld According to a quick search, eBay has lower costs. Which surprises me, because I looked up the costs of selling on eBay in the past and thought they were a lot. It depends a bit one a number of factors, like how many different products they put on the store, how much they sell, the type of items and a bunch of other stuff, but it does look like buying on eBay leaves the seller with more money in most cases. If they're fulfilling through Amazon, they might pay for storage and fulfillment, but I'm not sure if that arrangement means they have to pay additional fees from both sites. I guess I don't really know now.