Ooooh, a question right up my alley! I'm starting my PhD at a vet college, because I want to become a researcher of pet health. Also, I work in the veterinary industry and have cats of my own. While I have no real opinion in any case (ie not going to tell you one thing or another), I hope the following questions can help the OP!
Re: getting a cat as a Master's student - consider:
1) Do you plan on relocating after you complete your studies? If so, how far? Cats tend to not adapt well to changes in their immediate and permanent environments (often manifesting in behaviour and/or physical problems). For this reason, many behaviourists/veterinarians recommend avoiding air travel.
2) Do you foresee yourself spending long hours on campus, including working overnight? While cats tend to be more independent than dogs, some do need to interact with their humans from time to time. As cats are nocturnal animals, this could work well for a student who will be home at night.
3) How much do you plan to budget per month for high-quality food? Initially the higher quality foods appear to cost a lot, but these diets tend to be more nutrient-dense so you need to feed less than the grocery store foods. And bonus, smaller poops.
4) Re: number of cats - by nature, cats have different ways of interacting with other members of their species. Some cats prefer to be singletons, and adding another cat will be a source of stress for the original cat (as well as you). They may fight, or one may protest in other ways by urinating in inappropriate places (a form of territory-marking). Even if they do get along, having more than one cat means you'll also be spending more on food and vet care (even the preventative stuff such as vaccinations and routine bloodwork).
Overall:
Cats are great companions; I keep saying that they must be the easiest housepet anyone can have. However, when things go wrong, they can go very wrong - not necessarily anyone's fault, but because of how subtle cat body language is. So by the time a sick cat's owner notices problems, the problems may be so far progressed that maintaining the cat's care becomes extremely difficult. For example, we saw a case last week where the cat had lost significant amounts of weight (despite eating excessively). The owners held off on bringing the cat to see one of our vets because they'd assumed that the cat was simply diabetic until it started vomiting. To rule out other conditions, we ran blood and urine tests. The results showed that the cat was suffering from acute kidney failure as well as inflammation of the pancreas. After a few days on intravenous fluids, the cat has been sent home with several medications (a laxative, and an appetite stimulant drug) plus the owners being taught to give fluids under the skin (using a needle and line) to make sure the cat stays hydrated. They will need to do this for their cat for the rest of his life. Additionally, they will need to bring him in periodically for blood tests to assess his kidney function, which will cost them as well. Moral of the story: if you have a pet, get pet insurance