Drive in $6 + parking fee 
Used to park at Seah Im Rd for $4 full day
If you have a group of friends going with you, they can help to
share the cost. At least I have direct access to other places in
Sentosa. And it is not an everyday event to go there anyway.
don't forget the cable cars! The system recently underwent major
overhaul and its now travelling abt 20m higher than before.
Cable cars are more expensive than driving in.
