We were in IST a few years back and I saw some beautiful scarves. The sign on the stand said 2 for $20. There was a man in our group who said to the seller, "I'll take 3 for $20" and got it. So I went up and said the same. I probably would have taken the 2 for $20, but I needed 3 for gifts. I guess you can just stand back and see what others negotiate for and ask for the same deal.