Around how much do you think this cake from cake boss would cost?

Well, my brother is turning 4 in november and my family is planning on going to carlos bakery and get my brother a knight cake. You see, he is really into knights and armor and the movie narnia so we want this bday to be like a knight theme and special for him because on his last birthday his turtle died and it was REALLY! hard on him. So lets say if we got him like a medium size cake to feed 15 people, how much would that cost if you know? we will contact them is possible and do you have any ideas, something that has to do with armor but has a kid-friendly size. thankss everyone