What Mesos buy
Mesos pay for almost everything in MapleStory Classic World: potions and ammo from NPC shops, scrolls and gear from other players' shops in the Free Market, and the upgrades you need before each new area.
Why they're slow to earn
Monsters drop Mesos a little at a time, and the gear and scrolls players actually want sell for far more than a farming session brings in. Early on, every potion run eats into what you've saved.
Why buy them
Mesos go straight to your character, ready for the next weapon, a stack of scrolls or a Free Market deal, without the farming first. Bought during Founder's Access, they carry over to Grand Launch with your character.