The most common advice for anyone visiting Iceland is to buy your wine at the Duty Free Store immediately upon arrival. It is located right by the baggage claim area before you exit customs.
You are allowed up to 6 units of alcohol total. For wine specifically, this allows for common combinations like: where to buy wine in iceland
Prices at the airport are significantly lower—sometimes up to 25% to 50% cheaper than in town. The most common advice for anyone visiting Iceland