Thankot is a town of the Kathmandu Valley's western rim, 12 km from the centre of Kathmandu in Chandragiri Municipality. It takes 30 to 90 minutes to reach depending entirely on the traffic through Kalanki, costs as little as NPR 40 by local bus, and is most often visited as a half-day or full-day trip for the Chandragiri cable car, the summit temple at 2,551 m, and the Himalayan view from the ridge.
The cable car is the only substantial cost. Nothing else here charges an entry fee. Budget roughly NPR 1,500 to 2,500 per person for a comfortable day if you are a Nepali resident, or USD 25 to 40 as a foreign visitor, and most of that is the ticket. Everything else, the temples, the old bazaar, the memorial park, the two sacred ponds and the forest trails, is free.
The single most useful piece of advice on this page: go early. Mountain visibility from Chandragiri is a morning phenomenon in every month of the year, haze builds from mid-morning, and the queue at the base station on a Saturday can add an hour. A 07:30 departure from the city is worth more than any other decision you will make about this trip.