Are you having trouble with your children spending money through iTunes on your iPhone / iPad by buying games and then purchasing the in-app add ons to complete or enhance the game ?
First make sure you do not tell them your iTunes password.
Next you can set restrictions for In-App purchases
First go into Settings and General
Then scroll down to Restrictions and press on Enable Restrictions
Then put in a 4 digit password ( make sure you remember this !!!!!)
Then turn on In-App Purchases
Then change the Require Password to Immediately