Not many things are cheap in Norway.
Most tourists realise that fairly quickly.
Anyway, the diapers are subsidised by the state, but again and again, the diapers are very often sold out to foreigners who buy here and re-sell them back home.
If cars filled up with diapers are stopped by customs the fine is huge.
You can only buy for N. kr. 5000
Only India is cheaper than Norway when it comes to diapers.
Take a look at this : https://translate.google.com/translate?sl=no&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.ba.no%2Fnyheter%2Futlendinger-hamstrer-billige-bleier%2Fs%2F1-41-7542515&edit-text=&act=url