I just realised that I've never ordered anything from abroad so I'm not the most qualified to instruct anyone to order something from Finland. For example I have pretty much no idea about the payment methods. That said I can link two pages where one could find at least some Finnish Orthodox chant. I guess one could also find it elsewhere ( parishes, straight from choirs, secular stores ) but I think those have the most largest selection I'm aware.
http://webtuohus.valamo.fi/Click "Äänittee->" i.e. recordings on the upper left and then click

to find all of the recordings the Monastery of New Valamo is selling. Click "2" and "3" at the bottom of the page to move to second and third page of the selection. Most of them seem to be Finnish chant but not all. If you are unsure whether some recording is Finnish chant or not feel free to ask.
http://www.filokalia.fi/#kirkkomusiikkiThat's an Orthodox Bookstore run by the St. Kosmas' Brotherhood which was mentioned in the infamous Gaycult thread. All of the recordings before
Ulkomaiset CD-levyt -text are Finnish Orthodox chant.
Btw, they seem to have quite straightforwardly copied the idea of Orthodox bookstore from Frs. Serahpim Rose and Herman. I read Fr. Seraphim's biography on December and I began to wonder why an idea of their of bookstore sounded quite familiar. I guess St. Kosmas' brotherhood hasn't evolved into a monastery though.

Now how an Earth did found about that? I bought it about a week or so ago. This is about first time I hear Finnish Christmas carols which are Christian i.e. doesn't include worship of Santa Claus and elves and where the singers doesn't sound like that they are at brink of suicide. For some reason every Finnish piece of music seem to be melancholic regardless of how joyous the topic of the song was.