I have shipped several sets of wheels in recent weeks. I use two same size boxes taped together very well. I use enough padding to add weight, too. Fed Ex has averaged about $12.50 on all of them. I feel this is pretty reasonable.
When someone wants to charge Jerry $50 or more, I suspect greed in play.
I don't really know about how much coming from Canada adds to the cost.
Tom Sanders
Lansing, Mi