I get more partners overseas than Canada put it usually cost me between $22-$30 to mail over the pond. Again, I don't do it all the time, but I do try to say yes at least 3-4 times a year. I figure it is only fair to take my turn.
In doing the ornament swap I mailed out two lightweight envelopes as prizes overseas and each one cost me $13.50. One was to Australia and another to Ireland.
The table runner I just mailed overseas cost $22.50.
I do find that the USPS is the cheapest. Forget Fed-Ex. You will have a heart attack when they tell you the amount.