I just had an email asking about this so I will post the answers here.
Airports in Brazil have duty free stores on arrival (DUFRY is the brand) that permit US$500 in purchases above other allowances. The stores themselves administer the allowances, which give each arriving passenger a case of wine, whisky, other booze and also have lots of other stuff from food items to stereo systems and computers.
The prices are not as cheap ads they are at many foreign locations but the convenience is unbeatable. You can order in advance and your order will be waiting for you packed and ready to go.
The website is:
http://www.dutyfreedufry.com.br/