There is no possible objective generic answer to this question. The answer will be different for different people since different people will have different opportunity costs for eating frozen pizza.
For example, let us look at the issue of time. If a person is very busy, it may be worth it to eat convenience foods. If the person is very busy, the opportunity cost of cooking for themselves would be too great. They might be losing a great deal of money by taking the time to cook. They might be losing what little leisure time they have. In such instances, convenience food would be worth it.
The same is true if we look at health. It depends greatly on what a person would eat if they were not eating the frozen pizza. If they would eat salads and balanced meals that are not high in fats, for example, it would be good to forgo the frozen pizza. However, if the person were simply going to prepare themselves meals that were just as unhealthy, there would be no downside to eating frozen pizza.
Thus, the answer depends on the person. They will be able to save some money by eating convenience foods. However, they have to decide whether they would be able to have healthier food if they cooked for themselves. They would also have to decide whether it was worth the extra time taken to cook. So, they would have to balance the money and time savings against the potential gains in quality and health. Each person would have to make that decision for themselves.