This is similar, but different from the Typo sale (https://www.ozbargain.com.au/node/915326). There is a 30% off on online purchases at Cotton On (no code required).
In addition, the website says that if you use the code EXTRA20, you can get an extra 20% off. However, I have not managed to stack this with the 30% sale.
Delivery fee may apply based on the option chosen
Express - $9.95 or $4.95 on $70+
Standard - $6.95 or FREE on $70+
Deliver to Store - $2.95 or FREE on $35+
Store to Door - FREE
See https://cottonon.com/AU/delivery-methods.html for delivery options
Also, consider stacking this with CashRewards, which has a 10% cashback deal - https://www.cashrewards.com.au/store/cotton-on. This cashback rate ends on July 19.
Can stack with this for a further 10% off as well