Quick answer: Budget by category rather than a fixed total: transport, hotel, scenic-area transport/tickets, meals and seasonal activities.
Transport can be the biggest variable
Your starting city determines whether rail, flights or private transfers dominate the budget. Compare the full door-to-door cost, not just the ticket price.
Accommodation varies by season
Standard town hotels can be moderate, while ski-season resort stays and holiday periods can raise costs substantially.
Scenic-area costs are more than one ticket
Budget for the current admission structure plus required internal transport or shuttle components where applicable.
Leave a weather buffer
One extra night can increase hotel cost but also protect the value of the entire trip if Tianchi visibility or seasonal access changes.
Editorial note: ticketing, scenic-area access and transport procedures can change. Verify time-sensitive details with current official Changbai Mountain tourism notices before travel.