It is a well-known fact that cell phone service providers in Canada are some of the priciest in the world. When it comes down to the lesser of different evils, who should one pick?
First of all, what are you paying for? Some providers, like Rogers, throw in perks like premium Spotify memberships, which you might not be using or even know about. Make sure you're aware of all the things your getting and if you're not using them, switch to a different provider!
Next, make sure you're actually using the data you're paying for. Some providers will give you a pool that's shared with other devices on the account, which makes it easier to not leave data unused. Using usage tracking apps like My Data Manager make this simpler, and will help you adjust to a lower data cap if needed.
A recent change with the major providers is that they give "unlimited" data, with a 10 GB cap for the "full speed" option. While this sounds nice, many people don't actually need that much data, and would save money with a different plan.
It seems there's always a new promoted plan or special deal, like double data or free long distance, so make sure you check if there's a better plan for your needs at least every quarter.
If you buy your device at a subsidised rate, you're forced to go with a more expensive plan in some way or another. You've signed a contract that is costly to get out of so switching providers is more difficult. Carriers also let you buy the phone at full price, and then you get the bring-your-own-device rates. It's a higher cost up front, but in many cases, you'll save money over the two years that you'd have been locked in a contract, and you don't have the extra cost if you wanted to cancel. Your phone would still be locked to the carrier, so if you were to go this route, it's smart to buy straight from the manufacturer, and then you can get an unlocked device for the same price.
When you have unlocked phones and no contract, you can drop providers and switch at the drop of a hat, so if a different carrier has a new promoted plan, you can capitalize on that.
At the moment, my family's phones are on Public Mobile, a service owned by Telus. Public Mobile markets themselves as being SIM-only, because they don't sell any phones. This means that they aren't trying to get you to buy a new phone left, right, and centre, which is really nice. They also structure their plans around 30 or 90-day windows, rather than months, so your data budget per day is identical month to month.
Before you pick a carrier, do the math. All the math. The crazy difference that I like to point out is that the I could buy a phone outright with a credit card that charges 20% APR, pay it off in equal payments over two years, and end up spending $20 less per month than buying the same phone with a subsidized price.