A one day ticket for a child (which Disney considers to be ages three through nine) is Sixty-Eight dollars. If your child is above the age of ten then the ticket will cost Seventy-Nine dollars. There are other options you can add to your ticket will which increase the price.
Usually a child's pass at Disneyland depends on when you buy the ticket, if it is in season or not, and sometimes a travel agency can get you discounts. It also depends if you buy a package deal or not. Sometimes if you stay at a certain hotel you can get kids passes for free.