I saw a Youtube ad which said 35% off all Repco-branded items this weekend. I rang the local Launceston store and confirmed, but it's also only 25% on batteries. No auto-club or loyalty membership required.
EDIT: when I went to the store the staff there clarified that spare parts and batteries are 25% off, but all other full-priced Repco car care items are 35% off. Sale days are Saturday and Sunday.
Not often you see batteries on sale as well, plus this is a great opportunity to stock up on filters or brake pads.