What does it mean?
Koste skjorta, means that something “costs the shirt”. The expression comes from cost (costs) and shirt (shirt).
Essentially it’s used to describe something that is very, very expensive- to the point of it being a ripoff or not worth the price. This is because you typically wouldn’t want to give up your shirt in exchange for something else.
According to the Language Council of Norway (The Language Council), the saying draws from the English expression cost you the shirt off your back.
An alternative to this would be cost pork which means to “cost the flesh”, more specifically pork’s flesh. That term exists in both Danish and Swedish.
Both Danish and Swedish have their own versions of the expressions. The Danish version is slightly more dramatic and is cost the whites of the eyes (to cost the whites out of the eye), while the Swedish version cost the shirt (to cost the shirt also). However, the Danish version isn’t super widely used to our knowledge.
Previously it was much more common to say cost pork, but since the 2000s, the shirt has begun to catch up.
Use it like this:
It cost me my shirt to fly from Oslo to Greece during the summer holidays
(It cost me my shirt to fly from Oslo to Greece in the summer holidays)
Inger will buy a new laptop next month, it costs NOK 22,000. It costs the shirt!
(Inger will buy a new laptop next month, it costs 22,000 kroner. It costs the shirt!)