The majority of my 3-4 trips to Vegas each year are diversions from business travel. I can usually alter my itinerary for $40 or so and wind up with a long weekend there.
FREE. We're very fortunate,haven't paid for any airfare since '99. My wifes boss is super cool and lets us use his FF miles whenever we go to vegas(or anywhere else for that matter). Which reminds me have to get wife to book for 9/28-10/6.