How to get the total amount of Bitrix (quantity x price)?

Question

AJAX

I am learning Bitrix. I want to implement a simple thing. On the card page, display the total amount, which is formed by multiplying the quantity by the price. I didn't have any problems with simple items.
I decided to complicate the task of starting to use trading offers. And immediately faced with the fact that I do not know how to turn to the price of the selected trade offer. I understand that Ajax is indispensable. There is only one width property in a sales offer.

Answer 1

I want to do without using the standard functionality