Usually you need to pay the landlord for 2-months deposit and 1-month rent in advance. Then you do not need to pay the rent in the 1st month and can move in.
By the way, please do not forget the deposit for all utilities service
- Water (the Government of HKSAR) $400 deposit: you need to open the account and pay before you can use the services
- Towngas (The HK & China Gas Co Ltd.) $600 deposit: they will include the deposit in your first bill.
- Electricity: since there are 2 companies providing this service, it depends on the company you need the service. In general this will be about $1000.