The question you ask is one that can be difficult at times as every client & every order are different.
We as a company charge one hour each side for the design but if it is a new client that could possibly lead to new work then we would consider reducing it to half of that to get the order.
From a personal point of view just let him know you have reduced the cost as its a first time order then it will put you in good light for future work.
Hope that helps & best of luck 🙂