Oslo is not the cheapest city, but it should be possible to find accommodation down to around 500 NOK/day at Airbnb.
If you want to stay close to the Shuffle venue at Sentralen, the closest for cheap accommodation is the Perminalen just across the street from Sentralen.
Perminalen has rooms at 425 NOK/day per person for 3, 4 or 6-bed rooms, including breakfast, and double rooms for 960 NOK/day. It should be possible to book a large room together if you want to stay together with just Balboa dancers.
Two blocks away there is another cheap Poshtel (one step up from hostel); Saga hotel Oslo; 375 NOK/night for 4 or 6-bed rooms. Or 5 blocks away, the Citybox Oslo with double rooms for 770 NOK/day.
We have organised hosting for as many guests as possible. Unfortunately we have not been able to find hosts to all of the interested, and we don’t expect to find many more hosts now.