I have family in Canada & often ship presents out via M & S. Their website states delivery to Australia, New Zealand, USA and Canada is usually £15, but quite often it is free if you spend over £30.
I have received an email from them saying for a limited time, postage to these destinations is free, with no minimum spend.
There are obviously local taxes which might be payable by the recipient. But in my experience, when I've posted to Canada, if the value is below £35 no taxes have ever been applied. I have just placed two separate orders for roughly this amount to avoid tax which could be applied to an order with a higher value.