Here's the thing, plenty of folks run "all season" tires all year round and proudly proclaim they've never had an incident and don't need proper 'winter' tires. Perhaps, but it's been proven time and again that decent winter tires not only perform better on snow and ice in terms of turning and stopping, but also grip the pavement better when it's dry and cold due to squishier compounds that the tires are made from.
In that one instance where a deer jumps out in front, or some momentarily oblivious driver goes through a red light, or you just enter a slippery corner a bit too quickly, wouldn't you want to stop that 10, 15, 30 feet sooner? That's what proper winter tires can do for you.
In NS, you guys get some pretty significant snowfalls, so that's another reason to consider it.
And for the argument against winter tires because of the cost, figure that over 4-5 year ownership span, you'll likely need to replace a set of tires anyway. With a set of winters (which are generally more affordable than the '3-season' replacement tires) you'll reduce the wear and tear on the tires that came with your car.
As for retailers, pricing seems to be fairly consistent across the board now. That said, 1010Tires.com has always been a decent Canadian choice, but I'm sure others will offer up other suggested retailers. If you're happy with the dealership from which you bought your car, check with them, they often offer surprisingly good deals on winter wheel and tire packages because they buy such high volumes of them.