The previous 5% off promo has changed to 3% off now (buy any amount between $5-$500 and get 3% off). eGift cards can be bought using the SunCorp app.
Try this method if buying using their website: https://www.ozbargain.com.au/comment/8043999/redir
@jacksonjackson168 deserves credit too as I saw their comment in the earlier post.
Small, but easy 3% savings there.
Does this stack with Amex?