Basic Steps:
1 - Decide on the tire you want, first.
If you want a really good tire at a good price, consider using Consumer Reports or some other reputable source.
It can be worth a few buck in membership fees to find out what tires are good, and what aren't. Otherwise, it really is a 'crap shoot'.
Price is not equal to performance. Some are better in snow, ice, rain, etc. It depends on the conditions you expect.
Do NOT just take the recommendations of the person selling tires. Especially don't take the advice of the Crappy People on tire selection.
2 - Shop around for price.
Once you've narrowed the field to a few tires that will meet your needs at a losest suggested retail price, call around to different shops. Prices can vary widely among tire sellers for identical tires.
You might find a good deal at Crappy Tire ... but check around just in case. I ended up going to Kal Tire, last tire.
3 - Shop around for installation.
Use someone reputable (which means NOT trusting your vehicle to Crappy Tire). You can buy from one shop, and have them put on anywhere you like. Sometimes they'll give you a better price if you buy the tires from them. But maybe not.
4 - Buy the tires now, even if you install later.
If the tires you want are stocked by Crappy Tire, at the best price around, and they will give you an amazing deal on installation, and you think just this one time it's worth seeing if they can NOT screw up the work, make sure you BUY THE TIRES AHEAD OF TIME.
Since their 1970's-era "green screen" systems are usually NOT integrated, they might well sell your tires to someone else while you are waiting a week or more for your appointment time to roll around.
5 - Think seriously about buying Rims
It's a lot cheaper to switch them twice a year, and less wear-and-tear on the tires, to have both sets mounted on their own rims. Switch-over is quick and cheap. And, they don't take up any more storage space during the off-season.
6 - Consider buying in the U.S.
This is one product where the mark-ups are a LOT higher for Canadians then they are for U.S. consumers. For pricier tires, this could easily be hundereds of dollars.
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That's just my opinion, based on many a season of tire buying and installation.