A colleague did some work for me (which was his job anyway) and when I said thanks, he said "no thanks".
I was puzzled, and asked why he said that. He told me that an American once told him that saying "no thanks" is the same as saying "no need to say thanks", for situations where a person is thanked for doing his job.
Sounds like nonsense to me, but I thought I'd ask it here just to confirm.
Best Answer
Nonsense indeed. They are quite different, if only because "no thanks" idiomatically just means "No, but thank you for offering."
Funnily enough though, "No thanks necessary/required!" is the same as "No need to say thanks."