The park itself costs nothing — trails, campsites and beaches are all open and free — so the only real expense is movement, and without a car that means fitting yourself to a thin county bus timetable.
Oandu campsite
The state forest service campsite on the Sagadi–Altja road, about 70 km from Tallinn. Five campfire sites with fireplaces and a lean-to shelter, two picnic tables, a firewood store, an accessible toilet and room for fifteen four-person tents. No booking; drinking water is 300 m away at the visitor centre.
Sagadi hostel
The cheap indoor bed in the middle of the park. RMK runs a hotel, a hostel and a garden house at Sagadi Manor alongside the forest museum, a restaurant and a sauna, and the walk to Oandu starts from the door.
Oandu Visitor Centre
A 150-year-old forest district office 3 km from Sagadi towards Altja: maps, exhibitions on forest and heritage, parking, a well and a covered fireplace. Weekdays 9:00–16:00 through the year, with longer hours and weekend opening from 15 May to 15 September.
Getting around without a car
County buses reach Võsu and a handful of other villages, but they are infrequent and the sights sit 10–20 km apart. Check Estonia's journey planner before committing to a village base, and expect to walk or cycle between things once you are there.
What a day costs
The verifiable numbers are small. Trails, campsites, campfire sites and beaches cost nothing. Käsmu Maritime Museum is €8 adult, €6 concession, €18 family. The manors charge separately. Camp and self-cater and a day is close to free; the real cost is fuel or a hire car.