Try using Momondo.com or Skyscanner.com. I'm seeing some options that are under $800pp and some go through Toronto on Candianair. I'm in northern Michigan and have often found great deals leaving from Chicago. (Yeah it sucks to drive that far but to save $300-400 it's worth it. We stay at the ORD Hilton for $100 and $7 a day parking.)

If you're in southern Michigan you could possible train to ORD or Toronto.