Thought I'd share some of the experience I've gathered on driving a car opposite to what you are used to.
Like Finland, Canada is full of RHD cars available at great prices. The JDM scene tends to get mocked quite a bit, but I think that it is a great way to get a fantastic car. (So long as it is 15+ years old)
I purchased a TT Z32, a long time favourite of mine, for a very fair price. I had it shipped, quite literally, some one side of the country to the other. Price of car+shipping+tax was still under what you could expect to pay for a "regular" side drive.
Has relatively low Kms for the year, no problems at all ever since buying it. Passed inspection no problem.
Shifting with a hand you are not used to: takes no time to learn at all. After a while you won't even notice. It does take a while to get used to holding the wheel with the other hand as you shift, but really, it is a 0.5/10 on the inconvenience scale. Nothing to worry about.
Passing on single lane highways: These are all we have here. You need a very trusted friend, or a wide shoulder. If I'm getting ready to pass someone, I'll drive slightly on the shoulder. This gives me at least some idea of what is coming ahead. When it comes time to pass, I lean as far to the left as I can. Looks silly, but it works!
Left handed turns (In my case): I was warned that these would be more difficult... but no.
That's it! I highly recommend going for it! You'll get odd looks, lots of double takes, ect. I never did drive thrus before, but I did one in reverse just for the hell of it.
My take on the whole issue: If you can get a car for cheaper, and the only difference is the side of the vehicle that the steering wheel is on, why the heck not?
Be warned though, there are some very shady dealers selling banged up cars.(Nothing new though, I suppose) Buy from a trusted source, research, ect.