I did a quick search and Comfort Hotel RunWay (745 kroner for 2 person room on the 19th) seems to be one of the cheaper options in the airport area.
http://www.choicehotels.no/hotels/hotel?hotel=NO113But it is on the "wrong" side of the airport and if you need a taxi to get to the SCC area, you might be better off using the official SCC hotel. From SCCevent.com:
We recommend the Quality Airport Hotel Gardermoen, which is closest to the track.
Tell them you are here for the SCC and you will get a special deal!
The prices for the weekend(pr. night) are as follows:
Single room: 695NOK / 85€
Double room: 895NOK / 105€
Double room w/one extra bed: 1095NOK / 135€
Don't tell anyone I told you this
, but if you are bringing a tent anyway, you could probably get away with camping right outside the SCC area aswell