Now, I know First Choice is a chain, so there are other locations, but I can only comment on the Naremburn one, because I go there all the time.
This is without a doubt the cheapest bottle shop around. It is huge, and stocks a wide variety of wine, beers and spirits. It is open good hours, has parking at the back and the staff will always help you to your car if you get carried away and buy too much! One of the best things about First Choice, is the deals they have every day, not just the standard buy 6 and get 10% off, which they do as well. But every time I go in, there is always a new multiple bargain. For instance, one of the best I had was 3 bottles of nice white wine for $20!
The staff are very knowledgeable, and have always offered me excellent suggestions if I am not sure what to buy. If youre a local, start shopping here now and if youre not, find one near you, or come over to the North Shore, trust me you will still save money!