Freetown Gear and Gravel Lumiere Bike Helmet with Mips Protection
2 colours (white or black) to choose from in stock right now at the time of posting.
I bought this helmet for $55 in-store at Costco a few months ago and that was the cheapest it had been for a while. It was basically the same price (~$40) last year (https://www.ozbargain.com.au/node/748712), but now it's on sale again and in the last chance section, so unlikely to be re-stocked.
It's hard to find a bike helmet from an Australian retailer with 'Mips' for less than $100. Whether you think it's worth it or just a marketing gimmick, I'll leave up to you.
It has a built-in red LED on the back and reasonable adjustments.
Thanks OP, just wondering what battery does it take? CR2032?