Once you are arrested and taken to jail, your bond is normally set according to a schedule. A typical bond on a DUI case is $1,000. You must post additional bonds for each additional offense alleged by the officer (such as speeding or failure to maintain lane). If you give the sheriff's department cash for your bond, your money will be returned to you once the case is resolved (minus nominal fees). If you hire a bonding company to post your bond, you will pay them 12% for their service (unless the bond it greater than $10.000 then they can legally charge you 15%). After the criminal charge is resolved, you will not receive your money back from the bonding company.
In some counties, such as Gwinnett County, the police or sheriff's department will allow you to bond out of jail online. Check your particular county for the approved bonding companies and procedures. See the following links for help with your particular bonding procedures:
Gwinnett County Sheriff's Bonding Procedures
Hall County Bonding Procedures
City of Atlanta Bonding Procedures