I would make sure to bring as much of your kit as you can. Most rental places demo boats without a skirt, paddle, pfd, ect.
The outside world in Dawsonville (1 hour north of atlanta) rents demo boats. I think they are about $40 per day.
There are also demo rentals at the ocoee (rock creek) and the nantahala (NOC & Endless River Adventures).
If you want something cheaper you may want to look at GA Tech and Georgia State University. They both have paddle clubs. You may be able to rent from them.