I have been in Bangkok for 1 year. Sharing my real expenses. Salary 25000 baht. Condo rent 8000 baht for a 25sqm room near BTS. Electricity and water 2000 baht. Food 6000 baht eating out every meal. BTS transport 1500 baht. Phone and internet 600 baht. Miscellaneous 2000 baht. Total 20100 baht. Only 5000 baht left for savings which is not enough. Months with illness or social events leave nothing for savings. I think you need at least 35000 baht salary to live comfortably.