Qmobile X900 [i got as a gift] works with Chatr wireless (owned by rogers)
I assume similar smartphones may work too.
Main thing is, to ensure the mobile can accept the frequency range of North America.
So check the phone's specifications before buying to see if it will work in Canada.
(most probably it will work on Rogers network in Canada) as well as others.
Otherwise you can always buy phones here locally (new or used/refurbished).
North American GSM uses 850/1900 MHz , UMTS/HSDPA 850/1900Mhz, LTE 1700/2600, AWS 1700/2100 frequencies