One trick I have learned was the style of my husband in dealing with shops when we were abroad. Especially if the owner of the shop is there, my husband would engage the owner to a casual chat and in a little bit, he would hand a souvenir item that represents our country. There was a time he handed a 20-peso bill for souvenir which the shop owner was so delighted that she retaliated with a souvenir of her own - giving 2 shirts. It is a good scheme because you get to be friends. Last year when we were in Vietnam, the shop owner even became my Facebook friend so you can imagine the discount I got.