no hoax mail vs not a hoax mail

[Suthipong]

I got a junk mail wrote "I wish to inform you that this is no hoax mail or anything of such nature.
I would like to know that why they don't use "...this is not a hoax mail..."
What is the difference?

[Rover_KE]

There is no difference.

No meaning not a(n) is a common variation.

'I'm no artist, but I drew a sketch of the mugger's face.'

'He had us in stitches, though he's no great comedian.'

Rover

[konungursvia]

To me, "no hoax" refers to zero, not to a suspected incident, whereas "not a hoax" refers to a specific case suspected of being false. Usually.

[Suthipong]

May I ask some more question.
I have no money.
Why don't we say "I have not money."