Not sure how long the 20% casback will stay
Combine with today's only challenge in app for extra (Shop $50 for $5 Cashback)
Shopback app—>Account—>reward—>Find a Challenge
C&C is $5
You will need net spend $117.7 or $50 excluding c&c and delivery to get max / min cashback
Max cashback
$117.7+$5 c&c=$122.7
Cashback: 117.7 *0.85 *0.2=$20+$5 challenge bonus
(97.7-122.7)/122.7= 20.3% off
Min cashback
$50+$5 c&c=$55
Cashback: 50 *0.85 *0.2=8.5+$5 challenge bonus
(46.5-55)/55=15.4% off
Won't you need to spend $115-120?
Since GST doesn't count so to get the Full $20need to go above the $100?