The best place to buy MD for cheap is in obviously Asia (Japan, Korea, HK, etc) and from the smaller stores. Importing a unit can also work out quite cheap, more so than buying from the US depending on which model you want.
You can get very good deals in the UK, you just need to know where to look. I don't know about Europe but I believe the prices could be better than Canada as you'll need to add the price of a voltage converter in.