I missed this Thermos deal a couple months ago but thanks to @hgaoxhgaox, I bought an equivalent stubby insulator from Kmart for $5.
I was so impressed by its quality that I was going to buy a few as gifts for Christmas. Upon checking, it looks like this product is now on clearance at an even cheaper price of $3!
Unfortunately, only pink is available for online order.
Black is available in store (whilst stock lasts): https://www.kmart.com.au/product/double-wall-cup-and-drink-h…