Cost for previous conversation

I want to create an application that is able to reply to users in a more friendly way and give a more accurate answer (if it is required, ChatGPT will ask a question in return).

But in that case, conversation goes longer. As much conversation goes longer each time a call is made, the cost of the previous chat and the new message also increases.

but that makes it more costly.
for previous conversations on each token I have to pay.
So I want to request that you please don’t charge for previous chats or reduce the price for previous chats.