How to identify free trial subscription transaction

here is original thread

And I got a way to handle it:

By SDK upload introductory_price 😂

• introductory_price > 0 that means it is Pay as you go or Pay up front
• introductory_price = 0 means it is free trial

So here is another question, is there any api Apple could introduce for backend to query product price?

Looking forward to your response, sincerely!! :)