T3 parking. $10?
Skytrain to T1: Kids super excited!
Starbucks coffee to go:$5 per pax (optional)
T1 playground: Free
Enjoy the view from the viewing gallery and sip coffee as your kids entertain themselves: Priceless
Lunch: Up to you
Photo-taking at atrium T3: Free (Nice christmas decoration)
T3 basement toy shop; bring along a toyomi car, there is a big car track in the toyshop: Kids are really happy playing and trying to squeeze each other out, while your in-law and wife go shopping at NTUC. Good me time and switch off.
If you have spend more than $30 for your lunch, bring your kid to mickey house bouncing castle at Level 1 of T3, its free.
A day out with the family. Priceless