"No, thanks" with a comma, I think, means, "No, but thank you, anyway."

"No thanks" without a comma means "No gratitude; I didn't even receive a thank you."

I believe the same would apply to:

No, thank you. = No, but thanks anyway.
Example - "Would you like another piece of cake?
"No, thanks" OR "No, thank you." Good to both?

No thank you. = I didn't receive as much as a simple thank you for what I did to help him. Good?

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only "no thanks" is enough. I did not hear "no thank you" yet.
Mister Micawber/Wordy:

Do you agree with my logic above with the commas?

Students: We have free audio pronunciation exercises.
You are making a distinction that native speakers do not.

Would you like some tea? No thanks.

How about a donut? No thank you! Very kind of you though!
You kidding? I most certainly pause where the comma is... and I have been natively speaking for 31 years
No he's not. There's no aspiration between no and thanks, or no and thank you.
Students: Are you brave enough to let our tutors analyse your pronunciation?
LOL of course there is. "No, thank you" is the proper form. You cannot "no thank" someone unless you are a caveman maybe.
I'm a native English speaker, and it has occurred to me.
That's how I ended up on this page!
Completely agree with your logic. Most native speakers indeed do not use commas on a regular basis, which does not make the commas optional if you want your sentence flow to be smooth and readable.
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