Cash
From Inkipedia, the Splatoon wiki
Cash is the currency used to purchase items in shops, such as weapons and clothing. Cash can be obtained through multiplayer battles such as Turf War and Splat Zones, as well as through amiibo challenges. Gear bought with Cash can only be used in multiplayer battles while you are unable to use them in the singleplayer campain. The Singleplayer mode, Hero Mode, has it's own type of currency resembling fish eggs.
