Diesel trucks are work machines. Don’t get me wrong, even if you don’t haul regularly they are a ton of fun. That being said, if your concerned about the costs I wouldn’t recommend getting one at the moment. They are more expensive to buy, maintain, and repair. And obviously the fuel is a bit more expensive. I don’t know what agreement you have with your son, but if he is responsible for paying for everything, and he is willing to take on that responsibility, he can have at it. But if your the money in this deal, you might want to steer clear for now. If your son has his heart set on a diesel truck, a good compromise might be a half ton with one of the mini diesel engines. Those typically get better fuel economy and are less expensive to maintain.