Delta has round-trip flights from Dallas (DFW) to Vancouver or Toronto (YVR/YYZ) for $224-$238 with a connection. Flights October to May. Lots of weekends available. Origin/Destination reversible.
Note: Carry-on bag is allowed for free on Delta. This fare is “Main Cabin” NOT “Basic”.
Note: Travelocity has this for cheaper than the airline.