Originally I had only wanted to see the Northern Lights, but through the recommendations of some of the users here on TA, they suggested making side trips out of the lengthy journey to Tromso. However, after doing some more research, I find that it's increasingly difficult to do this on a tight budget in Norway. I'm not saying it's impossible, but it certainly creates many limitations -- many more than I expect from other European countries. At this point I may very well "get in and get out", i.e. see the Northern Lights and then leave as soon as possible.
So while I shall not be asking "Should I consider side trips on the way to Tromso, Norway?" I would like to ask what are some more affordable things to do in Norway? Thus far, I've been able to budget roughly $50 - $65 per day for most parts of Europe.
Update: I forgot to mention that I would be departing from Berlin and that I would be going in November/December. My apologies!