Oslo Hostels (Cheap!) and travel cases for instruments?

Any hard case (or flight case) of decent quality should do fine as long as the instrument sits tightly inside the case. if there´s any leftover room where the bass can slide around inside you can fix this by stuffing in a t-shirt or whatever. Also, slack the strings on your bass so there´s no stress on the neck.

Remember that there are no guarantees that it will arrive unharmed, but packing it tightly in a proper case reduces the risk to someone driving over it with a truck etc. That rarely happens.

I´ve travelled all over the world with instruments keeping these precautions in mind, and everything has gone well.

Some (American) airlines require you to sign away your right to compensation if your instrument is harmed (not disappeared) by the way. You should still have coverage on your travel insurance anyway, but you might check up on this beforehand.

If you bring your bass with you as hand luggage, show up early at the gate and talk to the crew there. It´s usually ok to bring it on board, but you don´t want to risk them sending it to the cargo bay in a gig bag....

As for hostels, Anker hostel in Oslo is decent.

I did study abroad in Norway as well and it was an absolutely fantastic experience. You've picked a great place to go!

That being said, for someone from outside of Norway things can seem quite expensive. Really it's what is cheap compared to other things there. If you're having a hard time finding someplace on the website you were looking at you may try Hostelling International. I booked the few hostels I stayed at in Norway through there and they seemed pretty nice from what I could tell. No frills, but they were pretty clean and we felt safe. I feel like staying at a hotel versus a hostel will be more expensive.

Also in terms of staff at hostels I never really noticed people to be rude or unpleasant to deal with. Norwegians on whole are extremely helpful and nice. But they don't go out of their way to talk to people they don't know it seems. Perhaps it was just a misunderstanding.

Are you wanting to stay in Oslo so you can travel around there for those three days? If not you might try looking at places to stay in surrounding cities. It may be a bit less expensive. The hostel in Tonsberg seems like it gets decent ratings, but it's maybe an hour or two by bus from Oslo. I know the one in Horten is still pretty new, but I did not stay there. But from there you could bus all around Vestfold.

Dunno if this helped at all, but if you have any other questions I'm happy to try to help out.