Found this on news.com.au of all places. Mrs Vietbargain will probably want more than one colour so I'll get one too.
Free full-sized lipstick samples at any M.A.C outlets, David Jones Counters and participating Myer stores in Australia.
"Customers must simply sign-up in store and follow us on Instagram @maccosmeticsaustralia to redeem a free Lipstick bullet"
edit grammar
edit2 I realised there's a djs @ barangaroo. Confirmed the deal is on. You fill out a form, follow on Instagram and get a free lipstick - but it seems like there's a set range to choose from and probably limited stock (looked like at least 100 at the counter when I peeked)
edit3 thanks to ncb123
MAC's instagram page put a post up (https://www.instagram.com/p/BXEv_3bFAro/?taken-by=maccosmeti…) confirming there will be lipstick giveaways tomorrow.
They've replied to some comments saying "all M•A•C stores, David Jones stores and select Myers are participating. The only Myer stores not participating are: Adelaide, Chadstone, Garden City, Canberra, Liverpool, Doncaster, Castle Hill, Joondalup, Penrith, Morley, Shell Harbour, Ballarat, Launceston and Tea Tree Plaza"
So all other Myer Stores that sell MAC other than those listed above should have some stock to give away.
Mod: Check with your local store to see if they are participating, there doesn't appear to be an official list (yet). Feel free to comment below to save others calling that store.
This is gonna be #1 post of the day.