From the 24th of Feb until the 2nd of March, Coles and Woolworths are offering 15% off iTunes Gift cards.
I'd recommend to save some extra money and go to Officeworks and ask for a price match. They also offer an extra discount, which will total to about 19.25% off original price.
Offer available on all denominations of App Store & iTunes Gift Cards excluding $20 and Variable App Store & iTunes Gift Cards from 24/2/21 to 2/3/21. Limit to 10 per transaction applies.