It's stock supply at my local lumber yard. Such places typically have lots of leeway in prices. Got something like 30% off when I told them it was going to be used to build crazy looking acoustic treatment.
Norwegian pries doesn't translate to anywhere. Everything is about twice the price over here. Translating the price directly to USD would probably only scare you away..
Have you tried contacting Dow or checking their website on who's your local supplier?