You can take a van. It only charges S$45 from airport to Festive Hotel.
Remeber to take out your hotel vouchers which can waive the toll fee via the bridge to Sentosa; otherwise, @$2 per car.
For inter cities, if your kids are under/or 3 years, you can take one taxi instead of 2. That's my experience.
If you take SMRT, from airport to Harbourfront Station, 2A2C only costs < SG$10. If you have hotel confirmation, u are free to take Monorail from Harbourfont Station to Sentosa. It's much cheaper!
airport to any hotel : SGD45 single trip
** this is same price for all 7-seat car,
this 7-seat car is on call service, if not go to airport, it is count by meter.
For peak hour 5-8 pm, there is 35% surcharge.
You may ask the hotel to call this 7-seat car for you when you already checked-in.
If you have SG local phone card, you may call the driver-Richard , SG code+92330884.
I called him from Hard Rock Hotel to SG zoo and China Town last week.
Benz 7-seat car require SGD50 single trip,
you may call from the airport where there is such transport service desk.