I tried following the same principle, and during a month I asked many different salespeopel whether he would bargain. I did receive a lot of “no’s”, but also a “yes” a couple of time. Even my favourite shop, where I buy shirts, gave me a 8 Euro discount on 2 shirts, provided I would buy two and not just one. Since I buy at least 10 shirts per year, that is a discount of 45 Euros per year. It might not seem much… but as they say, small amounts also count.