You have to follow the method described below to get it to this price
Credit for the method to get it to this price goes to sylon from this post: https://www.ozbargain.com.au/node/550308
The method copied from his post is:
Click the item and then add it via this "Frequently bought together" section: https://i.imgur.com/n6mwx4V.png
After adding in cart: https://i.imgur.com/DIuKvMb.png
The only difference from sylon's screenshots is that you will be selecting the R5 3600 rather than the processor that sylon selected.
Don't forget cashback