PRICES
The price in Oslo is 500€ per hour. And this is including coaching. The price without coaching is 300€ per hour (this is only for students who are part of a camp).
The price in Helsinki is 600€ per hour including coaching, and 400€ without coaching.
For prices as low as 250€, read
LEARN 2 FLY 4 LESS.
Accomodation
And getting to the tunnel.
Oslo:
When it comes to accommodation, in Oslo I would recommend the hotel next to the tunnel, Thon Hotel Gardermoen, click here if you would like to see it on Google Maps. Or click here if you want to go to the Hotel's webpage.
And getting to the tunnel is super easy, you just take the shuttlebus (S22) from the airport, it takes about 15 minutes. You can also take the regular bus, 420. The walk to the tunnel is a little longer, but not much, and it's almost half the price, about 4 euro.
Helsinki:
In Helsinki I would advice to get the tunnels bunkhouse, 20€ per person per night. 500m from the tunnel. Let me know if you want me to send you pictures of the place. It's a 2 bedroom apartment with large kitchen, own sauna and balcony.
And to get to the tunnel from the airport just take the train to the center, and then the metro. You can use the same ticket. ABC ticket in the HSL app. You can find the app here for Android, and here for Apple.