I've long played with "purchase parity" as a way to make more money. GoDaddy isn't scamming anyone, they're actually being really smart. If you're selling anything, you should be doing this as well!
Purchase parity is all about how consumers view the value of their purchase within their frame of reference. McDonalds is the king of purchase parity. The cost of a big mac meal in Encino CA is about $7. In New York City it's about $8. In the Ukraine, it's $1.20.
The Big Mac Index ? Historical Data from the Economist's Big Mac Index
It's all about charging what the market will bear. Some Canadian's feel $15 for a domain at GoDaddy is worth it (I don't, but others do). So GoDaddy is charging what the market will bear. If Canadians weren't willing to pay that much, GoDaddy would drop their prices.
If you want to get domains for less, I suggest masking yourself as Ukrainian ;)