Marketplace
CHANGEITUP30
30% off sitewide ends tonight 11.59pm.
Has been 30% off sitewide before in 2018, but 20% off sitewide is the more regular discount according to deal history.
https://www.ozbargain.com.au/deals/redbubble.com
If it saves you from browsing, postage is extra. It also depends on where it ships from but from what I've gotten T-shirts and Deskmats shipped from Australia, while stickers ship from the US last time the cost is not outrageous thanks to it only being "stickers".
Cashback as well if you have it.
PSA if you are using Google Chrome with the latest update. In settings go to Privacy and security>Privacy Sandbox and turn that off. Apparently it can mess up your cashbacks as mentioned here https://www.ozbargain.com.au/comment/12715619/redir
Mmm spicy fried chicken