Why do you think Vladek is such a conservative when he faces money?
In my opinion Vladek does not like spending money because of the hard times he faced.. When he was arested he had to make it with the little that he had. The outcome of all the suffering he faced shaped him in a different matter that originally he used to be. He had to shape his beleifs through a lot of pain, and hardwork thats why he is so harsh with his family. For example, when he states he needs to fix the celling. He does not ask for help, or hire someone. He believes that he can get his hands on work and fix it, with the need of no money. This just like many men in war are changed because of their experience in war.