Today HappySimpleLiving are giving some advice on websites that help you find free stuff. From those it seems that freecycle.org and craiglist have some tips in Sweden and Finland as well.
Another site I haven't tried out yet is justfortheloveofit.com that
help people to share stuff. Also on a lot of second hand website's you
can sometimes see people giving away stuff for free or willing to do a
trade instead of a sale ( great opportunity to get rid of something you
don't need as well!).
If you want to get a bit more extreme for getting free stuff you can always start dumpster diving. For people living in Helsinki there is a facebook group were people share the information on where in the city there is trashpallets were you might find stuff. I
learned about the group at my old office when we were throwing out old
office furniture that was in perfectly fine condition and my collegue
wanted to share the information to people interested in some desks. She
was not so happy about all the useable furniture that was gonna end up
at the dump. So hopefully somebody picked it up before the trashpallet
was taken away.