"Outfit Delivery Stamps
Whether you’ve attained multiples of the same costume, you have a ton of cute alts, or you’ve decided to change your main, Premium Membership has you covered. Every month you’ll be able to pick up a free supply of 20 Outfit Delivery Stamps via the Hongmoon Store, so you can send transferable outfit pieces to your other characters."
I'm a bit confused by this.. it's kinda vague. How would we go about picking them up? I just went to get them but ended up buying them instead by accident :/