Thanks so much to reader @n0placelikehome on Instagram for this tip!
They're back in stock HERE and they're still BOGOFREE! No code required--just add two brushes your cart and one will be free. As of the time of this post, ALL brushes are still in stock (none are sold out).
PS: Don't forget to use code MERRYMINI at checkout (they have deluxe Cover FX Custom Cover Drops samples right now!).
Thanks again, @n0placelikehome, for the great tip!