I have come to use mostly Priority mail when I sell clothing on eBay. First, because most items I sell fit in the Priority Mail envelopes which are flat rate of $4.90 at a post office or postal center (which is what I use because its a gas station near my house, closer than any post office and since its run by the gas station employees it's open 24 hrs).
Second, my customers seem genuinely surprised at how fast their items come (I think to myself - yeah be happy, but you ARE paying for it). I do charge them $6 for priority shipping to cover MY handling ( i.e. ink, fees, travel, whatever).
Recently, after years of being stubborn, I decided to use eBay's printing label system. And I was pleasantly surprised. For my flat rate envelopes its only $4.75 including tracking! Of course it is wear and tear on my own printer & ink, but it saves me tons of time! Instead of waiting in the huge line before Christmas, I'd just walk up to the front and put them on the side counter and say, already paid for! And it was all good! I'm so happy to have witched because I can know when a customer gets their item without having to pay the extra cost.