AV gas would be the cheapest route, but you need to know someone who can get you in the airport. Otherwise Rebel is about the only alternative. $8.00/ gallon for 100 race or $8.15 I believe at the Sahara/ I15 Industrial Rebel station for 110.
BTW I get mine from the Rebel on Lake Mead/ Van Wagonen. Not all Rebels have race.
Hope to see you out there this weekend, Lee!