Recent Baemin discounts for low-cost coffee pickups

Sometimes I can get a drink for just 100 won,
and they seem to hold pickup events for half price almost every week.
Theer Venti shows up most frequently,
but Compose, Paik's Coffee, and Mega Coffee pop up often too.
They are already low-cost brands, so seeing them sell like that
makes me wonder what kind of profit they actually make.