I want to stay at Lhasa for 3 days before undertaking a road travel to Kailash Manasarovar.

It is hard to tell you the exact cost. However, for the trip to these places, people usually rent a car for convenience and it may cost a little much. Also foreign travelers are not allowed to travel there on their own, so you have to join a tour. As for the quotation, you can consult your travel agency!