A plastic card
In Finland, EURO is used, in contrast to the Scandinavian neighbors, who retained their currency.
The most convenient way of importing a currency is a plastic card.
So, you do not have to puzzle how much money to change. Plastic cards are accepted almost everywhere. It is necessary to clarify. Say in Guatemala do not work Sberbank cards (and any Visa, Mastercard, platinum ...), other banks did not have problems. We had one case when one plastic card did not pass (Visa), we tried another (Mastercard) and it went through without problems. We somehow visited Finland were not far from the Swedish border and everyone went to Sweden to refuel (much cheaper). In this case, you would need more and Swedish kroner. The plastic card solves all these problems at a very favorable rate for you. Do not forget about Tax free