Car Rental That Accept Cash Atlanta Georgia Near Greyhound Terminal?

Hi, I am needing to reserve a rental or rent a car and would like to know if anyone can be kind enough to ist me with locating a rental place in vicinity near the Greyhound Bus Terminal in which I and a friend will be arriving.From there I will be going to Fort Jackson,SC and returning within a day.Are there any reasonable flat-rate rentals and do I have to let them know I will travel briefly out of the state of rental? Will they place an authorization lien on my credit card until I return the car and do all company do this,but what if I will like to pay cash? Also will the car rental be open 24 hrs because I will be arriving in the city pretty late around 1 a.m.? Any advice very much apreciated.. Thx