Does TCG offeres half day & night tours in Beijing and how about the price?

We are over to Beijing from 17-23 April. There are so many types of BEIJING tours to chose from I do not know where to start.
Qtn - Does TCG have any reasonable priced / not too expensive half day tours for 2 people to go around Beijing only?
Qtn - Private tour guides advertisd everywhere...Are they sfae or not?
Qtn - We want to know about reasonable priced night tours..Do you have any suggestions?