I've gotten great deals on ebay but, when it comes to leather I really need to feel it to know if I like it and the padding. I go to tack store to see what I like, sit on it, feel the leather and get an idea on pricing. If a friend has one I might be able to try it to see how it fits. Then I keep watching for it on ebay and I've gotten some great deals.
I think I've bought 4 saddles from there so far. Because I've seen the brand names in a store and sat it them, I've never been dissapointed with my purchase. I've had good luck with them fitting my horses too.
I can't imagine starting a young horse in a saddle that wasn't comfortable to me. Too dangerous, I'd rather be bareback than in a saddle that puts me in a chair seat, or that is too big or small.
Good luck shopping!