I stumbled on a bit of a glitch with the Big W website which allows free shipping on any $20+ order.
The code 'BOOKWEEK' is meant to allow free shipping for any $20+ spend on books or costumes.
- Add $20 worth of books or costumes to your cart and apply the BOOKWEEK code.
- Add whatever you actually want, still has to be $20 worth.
- Remove the books/costumes and free shipping should remain.
In my case, I had missed this deal (https://www.ozbargain.com.au/node/919945) which was an Amazon deal that had been price matching Big W. However, using the glitch above I was able to order a couple of cases through Big W with free shipping. Hope this helps someone.
Great, thanks OP!