I have no idea about the cost. I am on their mailing list and just got this.
"Dear Petrol-Heads Club Member,
As you may or may not know, nine racers have pre-paid to race The Real Cannonball. To muster a show of solidarity I'm hoping you'll consider purchasing an event T-Shirt, and wearing it the weekend of May 4th/5th to show your solidarity for the fools thrashing their scooters and themselves along one of three routes from Manhattan, NY, to Redondo Beach, CA. These Ts come in really kewl colors, are 100% cotton, double-stitched, and the screening logo colors are vibrant. All Zazzle profit will be donated to our charity, the Wounded Warrior Project. Please follow this link to see the T: