麻烦大家帮忙帮我些一份详细的茶叶买卖的英语对话，谢谢大家了。我等着急用！

Can I help you?
--Yes, please. Have you got some tea?
Of course, which kind would you like to choose?
--Do you have "Longjing"?
Yes, I do. The longjing tea in our shop is in very high quality, no matter the taste or the scent. So how much do you want?
--Three kilos,please.
Ok, here you are.
--Thanks!How much is it?
240yuan.
--Ok, here's the money. I have given you 300.
All right, here's the charge, 60yuan.
--I see.Thank you very much!
Not at all!