Sorry if there's a thread for this already.
There was, but the old advice is not relevant as the things change.
Phones is Canadian retail stores are still mostly locked to the providers (even if prepaid). The unlocked phone selection sucks.
You could consider buying a basic 7-11 phone during a promotion (like, right now) : $79.99 - $40 when buying a $100 top-up. That makes the cheapest smartphone you can get, even if it's not the best. I use definitely less than $100/year for the burner, so the smaller promotion (-$20 off with a $50 top-up) can be more useful.
Most bang for the buck is to buy better Chinese brands directly from China (on aliexpress or such), they are quite reliable now and still cheaper than Korean makes.
Downside is a potentially long wait. (More than a month is normal, unless you pay for a faster delivery.) The expected Canada Post strike can make it worse.