As long as you're 21 or older you can legally carry the Alcohol in your vehicle as long as the Alcohol is unopened.
So if you buy bottles or a case of beer as long as they're not opened you can legally carry them in your vehicle but it's best to put the beer in the trunk when carrying it just so it's out of sight.
Although it's legal to carry Alcohol in plain sight in most if not all States.
As long as the beer or alcohol remains closed and you never open it while driving it's legal to carry alcohol in your car.