We are asked this question every day. We called the CRA and had a long discussion about the laws when we established the webstore, and again yesterday - to make sure the laws haven't changed.
It is not Western Metal Incs desire to be the tax collector but we will follow the letter of the law to keep from being prosecuted. There is no end around from this tax - we are asked by customers "if the customer pays the freight can we show it as being sold in Alberta?" No - that is mentioned in the examples listed in the link below and we would be caught eventually. The fines and penalties are, in most cases, larger than the taxes owing and have been known to put a business into bankruptcy.
Readers Digest version - the taxes have to be paid based upon the tax laws of the province where the products are being shipped. If you want to check on this with CRA call them at 1-800-267-2384.
You can also see examples of this ruling at the following link. Once you are at the link go down the page to "Goods (tangible personal property) - click this option. Then go to "Sale of Goods" click this option. Then go to "see examples for general rules - sale of goods.
The picture below is the same page that the link will take you to after following the directions.
Thank you.
http://www.cra-arc.gc.ca/placeofsupply/