Here's a question for you to start:
Strictly for school costs (tuition, fees, any other random charges) and your apartment (just the monthly rent, not including utilities, food, etc.), how much money do you plan to take out in loans over the next 4 years?
I think the answer to this question sort of determines what kind of budget you should implement... at least in my opinion.
For example, if the sum of your costs is in the range of 100k-200k, I think you would be justified in spending a bit more on the "extras"--like a single apartment--than those who are facing down 400k in loans.
Ultimately, the answer to this question is different for everyone.