我要买这个。
I would like to take this one.

有没有别的颜色？
Do you have any other colors?

我可以试穿这个吗？
May I try this on?

你可以算便宜一点吗？
Can you cut me a deal?

我可不可以用信用卡付帐？
Can I pay by credit card?

在哪里可以换钱？
Where can I change money?

你们几点营业/打烊？
What time do you open/close?

我要买这个礼物送给我朋友。
I'm looking for a gift for my friend.

请帮我把这个包起来。
Please wrap this for me.

谢谢，可是我只是看看。
Thank you but I'm just looking