Previously answered here. Basically Hori and Wakamatsu have specific “payments”, Mikoshiba has probably made arrangements (ie. leaving many of his boobilicious figurines and games at his house), and Nozaki constantly feeding Sakura is maybe a way for him to return the favour.

Tsubaki said in Nozaki’s profile that wages will eventually be covered, so he probably does have a more proper way of paying them, but for now it’s not clear.