If you go to the post office and buy a single stamp it's $1.07 plus taxes but if you buy a booklet of ten it turns out to be 92 cents plus taxes a stamp. If you have scrap postage as I do it's also 92 cents (for a letter up to 30 grams).
As an example in Alberta it's 5% (GST only no provincial tax), while here in
Nova Scotia it's 15% HST (5% GST plus 10% PST).
GST Federal Goods and Services Tax
PST Provincial Sales Tax
HST Harmonized Sales Tax (GST plus PST) (the federal government collects the tax and remits the appropriate tax to the province (I think that's how it works)(the Territories and Alberta only charge GST).
If I buy from a store in another province they are required to charge me the Nova Scotia tax, if a store here in NS sells to another province they are required to charge the appropriate provincial/territorial tax.
I worked for the post office in Lake Louise, Alberta. You would get quite a few people coming through from Calgary to go onto Vancouver. I would always let them know that you're much better off buying stamps here. As soon as you go over the border you're going to be paying ~10% more for the exact same thing.
More clarification of the tax system was usually needed in the proceeding conversation
