I'm planning a trip to Shangri La next month probably mid Sept.

How is the weather during the month of Sept and October. I will probably spend a week in LiJiang before proceed to Shangri La. What is the flight fare(US dollars) from LiJiang to Shangri La? Is there any budget backpacker hostel in Shangri La? I'm a budget backpacker and should I take a bus instead of flight from LiJiang to Shangri La? What is the bus fare (US dollars)from LiJiang to Shangri La?
Please kindly share your tips or advises, greatly appreciated.
Thanks.