Any entrance fee payable for visit to Forbidden City and Great Wall?

Yes! The admission fee of the imperial palace is CNY 60 from April to October; CNY 40 from November to March.

The Great Wall has many famous sections, such as Badaling and Mutianyu. They have different admission fees. Badaling costs CNY 40 from April to October; CNY 35 from November to March. Mutianyu costs CNY 45. :)