You don't want to get a DUI, and you know that the legal limit in Georgia is a blood alcohol concentration of .08%. You do still want to have wine with dinner or go out to the bar with your friends; you just want to do it in a safe manner and obey the law.
What you decide is that you're going to buy a breath test. Before getting behind the wheel, you'll test yourself to make sure you are still under .08%. Will that be enough to guarantee that you do not face charges?
There are a few problems with this approach. The first and most obvious is that you can't guarantee that an aftermarket breath test is accurate. It may be, but the police use authorized devices. Yours won't hold up in court as evidence if it's different.
The second problem is more with a fundamental understanding of the law. You're not allowed to drive while impaired by alcohol. The .08% limit is where the court assumes you are impaired, but that's not all that the police look for. You can be under that limit and still impaired. If they have other evidence to show that you are, you can get a DUI no matter what your BAC is. Just checking to see if it's at .07% or below doesn't mean you won't get arrested, even if your test is accurate.
If you do find yourself facing serious DUI charges, especially in a complex situation where you don't agree with the charges, make sure you know what defense options you have.