Hello greggors. Canadian customs permits 200 grams of tobacco to cross the border duty free, whether in person or in shipping. The duty can be hefty, but is still cheaper than the cost of buying it in stores in Canada.
I live in Toronto and get most of my tobacco online. I have relatives in NY so I will frequently ship to them and retrieve it during visits. If my wife joins me that's 200g per person, so I can bring back 8 tins duty free.
But I have often had orders shipped directly to me. Customs permits 200 grams of tobacco shipped without duty, which means that I can order 4 tins from 4noggins (or elsewhere) and not worry about getting tagged. If I want to place a large order I just split it up so that each package is only 4 tins and pay for all that shipping, which is much much less than the duty or taxes. (I don't know why customs thinks that shipping 12 tins in 3 packages is all that different from shipping it in 1 package, but it is. Maybe customs gets a kickback from more shipping.)
I have ordered from some vendors who ship tobacco as a gift (I can't recall which, offhand, I'm sorry to say), but if it's tagged it'll have a hefty fine in addition to the duty. I had one shipment arrive from England that had five tins (250 grams) that got tagged, and I was hit with a $42 duty, which is a hefty duty but still cheaper than buying five tins in Canada in a brick and mortar.
There's nothing quite like tobacco: it's the passion of decent folk, and whoever lives without tobacco doesn't deserve to live.