Visiting the Kawah Ijen vulcano on your own is definitely the most adventurous and the cheapest. It can take up a lot of your time, but if you have some time on your hands, this option is worth it!
If you’re coming from Probollinggo, take a train to Banyuwangi. This will take around five hours and costs around 6 euros. Book yourself a nice accommodation in the village and check to see if your accommodation provides transport to the Kawah Ijen. If not, you can also rent a scooter and go there by yourself. It’s a 35-kilometre drive to the base of the vulcano.
If you want to see the famous blue fire, make sure you’re at the Ijen ticket office down at the base at 2.30 am. It depends on the mountain’s activity, but that’s the time the office opens most of the time. A ticket to the park costs 150.000 Rp (10 euros) for foreigners.
After you get your ticket, you can walk up to the park gate. Here you wait for the park to open, and from there you just follow the track that leads to the top. There’s only one path, so you definitely won’t get lost.
When you reach the crater lake, it’s time to go into the volcano to see the blue fire. Be careful here, because the track gets rocky. Check to see if there are other travellers going to the blue fire and follow them.