Big hotels and high end restaurants may have a tax ("service charge") of 10%-15%. All other consumer taxes are included in the price tag.
Tipping is rarely done in Tibet. If you go on a long organized trip through Tibet, your guide and driver will probably expect a tip of about ¥50 to ¥100 per person. Tipping can also be used as an extra "thank you" for exceptional service. In Tibet’s hotels and restaurants 5 to 10 yuan is acceptable to give to luggage handlers - more is excessive. At hotel restaurants you can tip 5 to 10 percent of the bill if you feel it is necessary.
Keep in mind that deciding what to do on tipping is not as simple as asking "locals" what they do. Firstly, people's expectations are keyed to ethnicity, and they may very well expect tips from a foreigner even if they do not from a local person. Secondly, service providers often go out of their way to provide special service to foreigners that they do not provide for locals, in part due to expectations of generous tipping. Thirdly, foreigners are often in places and contexts which cater to foreigners, and in which most locals will never find themselves.
In India, at least in a large city like Delhi, it seems middle class and upwards residents do make tips in restaurants, and will do even if a service charge is added to the bill, though they will reduce the tip accordingly.
Basic bargaining skills are essential and expected in small shops and street stalls. It is also accepted at hotels, travel agencies, pedicab drivers and with people but not everywhere. Make sure to be polite and keep smiling. If they don’t want to allow the price to go down, try walking away and they may call you back and accept your offer.
David Germano