Norway is an expensive country, with Oslo consistently maintaining the dubious title of one of the most expensive cities in the world. Cost of living is about 30 percent higher in Norway than in the United States and 25 percent higher than the United Kingdom.
The standard of living in also among the highest in the world. Healthcare, education, transportation are all excellent and residents make a very reasonable wage. The high cost of makes anything seen as a service more expensive.
Day-to-day living costs bottom out at around 600 kr/day by staying in hostels and avoiding restaurants. A more comfortable budget would be around 1000 kr/day with about 2000 kr/day needed for good hotels and restaurants.
Alcohol and tobacco are some of the most expensive items you can buy. A 400 or 500 ml beer in a pub will cost upwards of 60 kr. Cigarettes cost about 80 kr for a pack of 20. Even fast food is more expensive here.
Many Norwegian's bypass these costs by buying supplies in their cheaper neighbor Sweden.
For short term housing before you settle into a more permanent place, there area variety of hotels, sublets, hostels, and short term housing.
An important trait in any roommate situation is having boundaries and a clear understanding of what each roommate requires. To protect yourself against potential problems should the worst happen, try to arrange it so that your roommates co-sign the lease. This makes all the roommates responsible for whatever happens to the property. If the worst was to happen, such as your roommate losing their job and not being able to pay rent, they will be held financially responsible- not you.
Tram 11-12-13-17, bus 30-31 to Hausmanns gate.
Haraldsheim Youth Hostel
The biggest HI hostel in Oslo is just outside the main ring road. Both dorm accommodations and separate room with baths for 330 NOK/person with breakfast included. Reception is open 24 hours.
Tram 17 or bus 23-24-31-33.
Outside the city border, extra fee needed if you have Oslo Transport card. Open May-August.
Train to Stabekk, or bus 151, 153, 161, 162, 252 or 261 to Kveldsroveien
Rafanningen Youth Hostel
Open June-August, inconveniently located but nice.
Tram 11-12-13 or T-bane 4,5,6 to Storo, change to infrequent bus 56 to Rafanningen.
In the center, this hostel is slightly more expensive and slightly higher quality. There is a cafe with traditional Norwegian meals at decent prices.
T-bane to Stortinget, bus 30-31-32-54 to Wessels plass, tram 10-12-13-19 to Kongens gate.
Part of Hostelling International this search engine offers 75 different kinds of hostels from north to south. You can book single, double or family rooms online.