Just got store credit for buying a battery at 20% off last week, now dropped to 30% off for most Century Batteries - however does seem to exclude 4wd batteries.
Don't forget you can also buy discounted giftcards for SCA and stack them with Shopback and Cashrewards which both have 2.1% cashback currently.
Ah shit. Just bought a supercharge over the weekend coz century wasnt on discount At autobarn