Here's how you ask what something costs in French.

These are the phrases:

How much is it? - C'est combien?
How much does it come to? - Ça fait combien?
How much does it cost? - Combien ça coûte?
It's one euro. - C'est un euro.
That comes to 2 euro. - Ça vous fait deux euro.
It costs 15 euro. - Ça coûte 15 euro.

This video comes from the Lexicogs Getting Started in French course.

To learn more, please visit:
https://lexicogs.com/how-do-you-ask-how-much-something-costs-in-french/