Zeny is the currency in Ragnarok Online. When things are denoted in "Z," that usually means Zeny, as in "Selling Item X, 100,000 Z!"
A single character is limited to holding 1.000.000.000 zeny at a given time. While engaged in a trade with another player, if either player attempts to add enough zeny to put the other player over this cap, the trade will automatically cancel. Additionally, a single trade is limited to 1.000.000.000 zeny at once. If you need to buy or sell an item worth more than 1 billion, you can convert your zeny into coins at the coin seller NPC in north of Asgard.
If an item sold through the Vending skill would put the seller over the 1b zeny cap, the transaction does not processes and the item is not purchaseable. Previously, the player buying the item lost their own zeny, gained the item, and the player vending received no zeny at all.
- Main article: Making Zeny
As Zeny is the main currency in the game, how rich a player is or how much gear and items they can afford is reliant on how much capital they have in terms of Zeny. Zeny mostly originates from selling items to NPCs, but selling to older players who already have large amounts of Zeny is usually the main method to attain decent wealth. The basics start with selling items to NPCs and Vending. Some items that have a high value can be hunted or obtained through Quests.