Here is a photo of Helsinki's bar tram.
I took a trip in the tram once when I was an MBA student here. I remember that the first beer was included in the ticket. I don't remember what it cost. Then again, if you are concerned about how much drinks cost in Finland, then you have no business drinking in Finland! (Unless of course, you are bringing your alcohol in by the carload from Germany or Estonia.)
Helsinki's "pub tram" celebrates 10 years - Helsingin Sanomat