mesheel, you’re not listening. Inventory is your problem. If you do the work to photograph, post and market a piece on the internet, only to have the store sell the piece, that’s your problem. If somebody orders the piece from you before you know it’s been sold, that’s a big problem. Given that most businesses I’ve seen in Taiwan have atrocious recordkeeping, there may well be a big delay between the owner selling a piece and telling you. In fact he may not think it’s important to tell you at all - at least until you tell him that someone wants to buy the piece.
On Ebay, it’s a violation of the terms of service, and will give you bad reputation at best and at worst will get you banned from Ebay and have your Paypal account ‘frozen’ (money gone, all gone, forever).
Shipping is also your problem as you will recieve any letters of interest. And the first thing they will say is, “I’m interested in piece X, but how much will the shipping be?”. Now, you won’t have a solid order, you can’t just pack it up and weigh it, but you will need to come up with a price IMMEDIATELY - because nobody likes too be kept waiting. And if it turns out to be higher than the quoted price, are you going to risk the sale by saying “Oh, it turns out shipping was a little more than we first thought - actually, a lot more.” No, you won’t. And will the gallary owner be nice and say, “Oh, that’s OK, just a mistake, I’ll take care of the extra shipping.”. No, he won’t. You’ll be the one paying. If you pay, it’s your problem.
And if you don’t do the shipping yourself (it is a lot of work), you will never get a good feel for estimating shipping costs on varied objects. So this will happen to you again and again.
MaPoDurian made good point that the absolute minimum that you should consider is 30%. You can, of course, make this up by marking up the price. You should also have the customers pay you directly. Not just because it protects you but because you will have to deal with any problems, in effect you will be legally responsible, so you’d best have your hands on the money.
10% is a joke. Surely any good customer gets more than a 10% discount.
To be honest on most pieces I would only consider it reasonable on a 100% markup, as you are taking major risks, and on a few pieces the prices might still be attractive to Americans.