It doesn't matter.
这没关系。
It was nothing at all.
根本没关系。
It doesn't matter about the price.
价格没关系。
It's alright,sir.
没关系，先生。
thanks anyway.
没关系，谢谢。
Yes, that's all right.
可以，没关系。
Do not mention it.
不客气。
You are very welcome.
不客气。
Don't mention it.
不客气。
You is welcome.
不客气。
Offensive in manner.
不客气的
Tax official: you are welcome.
税务局：不客气！
No trouble.
不客气（没有麻烦）。
Please do not mention it.
请不用客气。
You're very welcome.
不用客气。
His answer wants politeness.
他的回答不够客气。