Walked past 7eleven today and saw that they had 20% off iTunes cards and the link confirms this. Might be quicker to pop down to your local 7-eleven instead of Woolworths which has 20% off as well.
There are currently 2x$20 cards for $30 available from Harvey Norman, Game, Target and Myer but there are generally more 7-elevens around and you don't have to buy 2 in one transaction from this.
unless you live in SA :P no 7/11 there :D