No, in Georgia, there is no grace period to return a used car if you change your mind. The GA Office of Consumer Affairs notes that people need to understand that when buying an 'as is' vehicle it means as is and the moment you sign the paperwork at the dealer's lot (or buy from a private party) the vehicle is now yours. Their representative added that contrary to what many consumers think, there is no three-day grace period to return a newly purchased vehicle.
There are lemon laws in Georgia but these pertain to new vehicles. The Georgia Lemon Law is a self-help statute whose primary goal is to have the manufacturer of your motor vehicle fix any defects. If your vehicle cannot be repaired in a reasonable number of attempts and is found to be a "lemon," the law requires the manufacturer to replace or buy back (repurchase) the vehicle. So this law could not help you with a used car that you bought and want to return.
The Georgia Office of Consumer Affairs notes that when buying any car you need to check the car out thoroughly. This is very important, because all vehicles are sold AS IS unless otherwise specified in writing. "As is" means NO warranty, and verbal promises may not apply. Unless you have a specific written promise or purchase a service contract, the seller of an "as-is" vehicle may not be liable for any problems the vehicle has, or for any repairs it may need, once you sign a purchase agreement.
This GA agency also states that unlike some other purchases, there are few remedies for car-buyer's remorse (that is, changing your mind). Contrary to a popular rumor, there is no cooling-off period or statutory right to cancel a vehicle purchase contract, and in fact very few dealers will agree to allow you to cancel. In essence, once you have signed the contract, you have bought the vehicle, even if you have not yet driven it off the dealer's lot.