Would like to know if working in Singapore now how much money estimated need to prepare?
For example how much is the average room rental and deposit, electronic stuff, groceries and living expenses etc

Thank you.

Should allocate at least S$1K for room rental, even for govt HDB flats. Meals are around S$10-20, depends on what you eat, whether hawker stalls or fast food. If your salary does not exceed S$5K, it would be quite hard to live a comfortable life in SG.

Bring 2 months worth (for a 1+1 room rental)
Spare 1 month rental

Food for 2 months because bank acc setup is not instant if you arrive on long holiday. Plus payroll cycle

Basically looking at around $6.5k for the above at bare min