Westjet is showing direct flights from Toronto to Las Vegas round trip for the price of around $309 nonstop!
Go to Expedia.ca and Search for a flight from Toronto to Las Vegas (LAS)
Use following sample date combinations:
Nov 21 to Nov 28 or Nov 29 or Dec 5 or Dec 6 ($309with non stop)
Nov 28 to Dec 5 or Dec 6 or Dec 12 or Dec 13