Received the code "SHOP 20" through an email campaign, but it's not targeted and can be used multiple times.
Do note the space in between SHOP and 20 is required or it won't get applied correctly.
No min. spend: if the item is $20 or less you'll only pay shipping to have it delivered to your door (in my case [Sydney Metro]: $5.95).
In theory the code should also work in-store or pick up, I haven't tried. Seems unlikely they would honour those, but you're welcome to try.
T&Cs:
*$20 store credit cannot be used in conjunction with other offers.
Redeemable online & in-store until 4th Oct 11.59pm AEST
Nice find OP. Just grabbed some smoking chips for postage only.