It starts with the decision on how long you want to stay. Taking into account that it is quite expensive, this isn't the destination where you want to just "hang around" somewhere unplanned for a few days in one spot.
Standard rate is an all-in fee (transportation, accomodation, guide, food) of USD 200 per day plus USD 40 extra if you are alone or just two travelers plus visa fee of USD 20. In peak season (Mar-May and Sep-Nov) the all-in fee is USD 250 per day.