haven't stayed there personally, but from what i've heard: NOTHING's cheap in oslo. maybe couchsurfing could be the thing for you? i love it... (www.couchsurfing.com)

so I was there in Oslo and I can only say what the others already said: it is really expensive.. if you know somebody, I'll rather go to them.. it is up to you. An example what a drink ( cola costs 1/2 l): 20 NOK :it is about 2,50€ 3,70$ 2,30£ This are the lowest price for a coca-cola which I found in Norway/Oslo

nothing is reaaly cheap in Oslo, but you can stay in the Haraldsheim Hostel, it's conected to the International Hostelling.... they're clean and gentle.. and have breakfast.

hostleworld.com

I stayed in the Anker Hostel, good but not very cheap, in fact Oslo is a expensive city, so be prepare!!!

oslo is very expensive, small and poor hotel in Bergen is about 300 euro for two or three days for two people. our private experience :)

thnx)