What are the rules?
If it was being shipped from B.C to say Ontario it would cost double what it would only going a few provinces over. I'm not sure what postal codes you used for the $18 estimate?
Anything going from Ontario to B.C starts around $14 as the basic minimum, and anything going within province or next province over starts around $9 basic minimum...I work at the postal outlet in the mornings at work and it is cheaper to mail things to the states than it is to mail within Canada!