How much does it cost to create an app?

How do I create a free app for my business?

I can't say anything because I don't know how much knowledge and technical skills the questioner has about making apps.
If you are a beginner, I think you should read through some books.

How much does it cost to create an app?

It depends on the size and requirements of the application.
If you haven't done anything at all, you don't need to think about the cost now.
If you haven't done anything at all, there is no need to think about cost now. Let's learn first.