Here's a list of all phone models which support all 3G/4G Telus (and Bell, Rogers, Shaw) radio frequencies/bands and which have dual-SIM slots.
https://www.gsmarena.com/results.php3?s3G5s=HSDPA850,HSDPA1900&s4Gs=2,4,5,7,12,13,17,29,66,71&sNumbe...
This list is mostly the latest and greatest versions of iPhones and Galaxies, of course.
But there's also some good devices on the list which aren't overpriced fashion items - the OnePlus and Moto G families are good choices with a variety of models to fit every price range.
Another option is to simply buy an "unlocked" phone from London Drugs, Staples, Walmart, etc. Be sure to confirm it has radio compatibility with whatever network(s) you'll populate into the second SIM slot.
Beware that most dual-SIM phones are "passive" or "inactive" - that is, only one of the two SIM cards can actually be active at any given time (you switch between them with software and/or device restart).
If you need both SIM cards (phone numbers and services) active simultaneously then you'll need to choose an "active" dual-SIM phone - and the added cost tends to work out almost as much as just buying a pair of cheaper phones.
If you buy a phone online - especially if it comes from eBay or Alibaba - then you must examine the model/submodel/variant carefully. It might be intended for a foreign market (Europe, India, China, whatever) and not work in Canada (radio-incompatible or software-/firmware-lockout, etc). Indeed, it might not even have an operating system and UI written in a language you can read.
