5-7 It's my treat. 

  It's my treat.    It's on me.   Let me pay.   Be my guest.   I'm paying.  

I got it.  Don't say a word.   It's my pleasure.   Next time you can pay.
 

5-7 我请客。我请客。让我付钱。我请客。我来付钱。

我买单。不要争。这是我的荣幸。下次你可以付。