If they ask I just declare what I bought and pay the hst on it as if I had gone and bought it from a store in the states.
Perfectly legal and half the time if the amount is under $100 they don't bother charging you.
I think the handling fee is $5-$10 depending on the size of the package and how long you leave it there.
That's how I will be getting my next order of double wide DVD cases since it's difficult to get the ones I want shipped to Canada.