This is a repost of what i did a few years back.
いくらですか (i-ku-ra de-su ka/How much is it?)
その値段はちょっと。。。（sono nedan wa chotto…./That price is a bit…)
ちょっと負けてください。。。(chotto ma-ke-te ku-da-sai /Please give me a little discount)
In most big department stores, you can get a tax refund if the price exceeds 5,000/10,000 yen. But most of the time, there’s isn’t. So be thankful if they give you a discount and say ありがとうございます (a-ri-ga-tou go-zai-ma-su) (^_^)