Finland has a rather unusual electricity billing system. Comparing to other European countries, it may seem strange, but in Finland you must pay your electricity bills once after 2 months of using the electricity, instead of doing it every month. You may get scared of not getting your electricity bill at the end of the first month, but rest assured that at the end of the second, you will receive a total bill for those two months together. Usually, you get used to such a system pretty quickly and it helps to think over your budget for a month more carefully, knowing whether you have to pay for electricity this month or not.
One more serious thing to keep in your mind is how you need to pay the electricity bill. In Finland you must pay for the electricity you spent and its transportation separately. There are different companies providing this for you: you can make an agreement with only one of them or make two different agreements with the different ones (one for the electricity and another for the transportation).