My studies require moving from one university to another. The distance is not that long from Helsinki to Oslo but most car renting firms are not renting car here for abroad trips. Which van renting firms operate in all Nordic countries so I could rent the van for the move?
I know that at least Sixt allows you to rent a car from Finland and drive it in other Nordic countries, including Norway, but you have to let them know about your plan to drive it abroad before you rent. You also have to be at least 21 years old to rent a van type car.
They also allow you to just take it one way, but the cost for that is pretty steep (~1400€) for someone with a student budget, so it's very much worth it to drive it back to Helsinki and then fly back to Norway instead, saving you around 1000€ for one days effort.
We've recently used a 'man with a van' to move some of my fiancée's belongings from Finland to the UK. We found him on a Facebook group for FI-GB expats who were recommending him to other members.
It cost around €300, which is about a quarter of the cost we expected to pay if we'd have gone with either the quotes we'd had from 'official' moving companies, or the costs of renting a vehicle to go either one-way (with one-way charge) or two-way (with the additional fuel and time costs to drive it back).
I'd recommend finding a friendly, targeted FI-NO Facebook group or contacting Suomi-Seura (Finland Society) who hold a directory of businesses.