Any good learning/teaching application(apple IOS) or youtube channel for kids to recommend?

Best is free, or one time purchase to access everything.
Those monthly fee application is too expensive.

Is using application to teach kids a good choice?

Anyone tried My dental care by citibank(ACE insurance) before?


http://www.citibank.com.sg/gcb/insurance/mydentalcare.htm
http://www.personalinsurance.com.sg/MyDentalCare/coverage-and-premiums.aspx

it's a insurance by ACE. Look too good to me, are there any catches or hidden stuff?