How to budget true cost of living for a new grad in a big city?

[AaronHC]

I'm a recent graduate starting my first salaried job in a major city, and I'm trying to create a realistic budget that accounts for the true cost of living beyond just rent and utilities. I'm shocked by grocery prices and transportation costs, and I'm worried I'm underestimating irregular expenses. For others who have navigated this transition, what are the most commonly overlooked budget categories for a single professional? How much do you realistically allocate for things like healthcare co-pays, household supplies, and occasional socializing? I'm also trying to decide if getting a roommate is a financial necessity or if stretching my budget for a studio apartment is worth the privacy and mental space.