Is it correct - “How much each banana costs?” And let me know is there any way to ask this question

How much does each banana cost?
(‘Each’ makes the term singular)
How much does a banana cost?

A shorter, common sentence is:
How much is each banana?
How much is a banana?

You could also use ‘what’:
What is the cost of each banana?
What is the cost of a banana?

You could also ask:

Excuse me. Could you please tell me HOW MUCH EACH BANANA COSTS? / I wish to know HOW MUCH EACH BANANA COSTS. (No comma this time, for it is not a direct question.)

Hi James,

I suppose you could say that, if you wanted a longer, more verbose question.

I don’t understand you comment about the comma though. Did you mean ‘no question mark…’?)

Yes. Thank you.