An update to this: The offer expired yesterday. Then I however was prompted that the normal price was 2350 NOK, but as a new user I could get it for 150 NOK for the next X hours. So just a new offer with the same price lined up after the first expired.

Earlier today I checked, and then the price was back at 2350 NOK. However, checking again now a few hours later, it's again a new offer for 150 NOK as a new user. And if I log in, it's 250 NOK without any mention about why, just a "90% off!" tag.

So yeah, the full price is a fake one.