In the supps right off the ARRC website.

"Make checks payable to “SCCA – Atlanta”. Your entry fee will be automatically returned in the event that you are unable to attend and entry fee checks will not be deposited until after the event, so there is no reason not to register early. A $25.00 charge will be assessed for each returned check. Primary driver is responsible for all fees for his or her entry."

Since there is NO registration at the track and can only be accomplished online through DLBRacing.com Online Registration System I would suggest you use a credit card or Paypal.