$500 is nothing compared to having your butt hauled to jail for breaking copyright.  Odds are that the company who is organising the show will have a clause about that.
You can bump all week long, but I would be surprised to see anyone sticking their necks out for the trouble.
And your trouble too while we discussing it.   

Call these guys, they might rent you a machine for your booth:
Mountain Coin Machine Dist. 
5675 S. Valley View 
Las Vegas, NV 89118 
Telephone: (702) 798-0900 
Fax: (702) 798-8431 
Tell them I sent ya.
$500 sounds right for a day or two.