Do Scandinavian countries like Denmark, Sweden and Norway accept each others currencies?
They are not all on the euro and you generally can’t use money from one directly in the another of the countries. I spend time in Lund, Sweden sometimes and visit Copenhagen and other places in Denmark as well as Sweden. You can just use your ATM card and get the currency you need in each country. As for souvenirs, Swedish glass is quite nice or a hand carved dala horse. Royal Copenhagen porcelin is a good choice from Denmark or maybe something from Georg Jensen. Norway sweaters or woodcrafts are nice. There are always the typical t-shirts, etc.