$283USD YYZ-PDL on SATA. These are direct flights, round-trip, taxes included.
Fairly wide availability. Use kayak.com to search for dates. Example dates.
Book on Orbitz or Cheaptickets.com
You can also use ITA Matrix to find dates that work well (you cannot use ITA Matrix to book though. Find the dates then input them into Kayak).
Also, DON’T CALL THE AIRLINE OR THE BOOKING COMPANY.