Alright if you want to be in "Bull Run" it will cost you something in the range of $17,500.00. For more information on joining the ralley check out the site:
http://www.cardomain.com/features/bullrun_2007_contest
There is also a "Bullrun" that the entry fee is less and your car can cost no more then $1,000.00, and you must be willing to sell it at that price, or something like that. anyway just thought you might want to know.