Marketplace
GIFTMODE
Expires today at 4pm AEDT
This is meant for CA, UK, and US users only but it seems to work for AU addresses if you set region/currency to the one of the above three.
Stacks with shop coupons.
I also learned that you can get 4% cashback via US cashback site Price.com, which is more than triple what CR is offering. $5 bonus on referral signups (must download browser extension).