For those of you who (i) work in CBD, (ii) 30 years old or younger, (iii) track your spending, I am wondering what is your average monthly expenses (in absolute amount)?

Nope for me

On food - I know it's difficult to aim for $5/meal in the CBD area, but it is possible provided you brave the long queues and stuffy hawker environments. I still try to target that though - Amoy and Maxwell if in the Tanjong Pagar area. Unfortunately for Raffles Place, the cheaper food options have decreased with the moving of Golden Shoe Hawker. If I am super frugal about it - baseline of $5 per meal ie. $10 per day (2 meals) and total of $300 a month.
Exercise is my entertainment - so I have a gym membership which costs a little over $100 a month.
Transport - on average $3-4 a day with public transport. So $120 a month.
Shopping - don't really shop unless I need to replace something.
So the range is $500-$1000 - with the latter being me not being so frugal when it comes to food and other snacks.