Keijohostel is probably the cheapest hostel in Helsinki. 13 euros for dorms, and 30 euros for a room and 17 euros per person for double bedroom. It is not too close to centrum, but many busses and trams from Central Railwaystation get you here. Just write«Keijontie 10 «(and your starting location of course, check the nearest building. Tickets are about 2 euros, one day ticket 7 euros, week ticket is 28 euros, so take it) here: