On the Classic server, L2 Coin can be obtained by hunting monsters or can be purchased from the L2 Store using NCoin.
On the Aden server, L2 Coin Boxes can be obtained by defeating specific raid bosses, earned from special events, or can be purchased from the L2 Store using NCoin.
Note: The L2 Coin Box is a tradable item, but the L2 Coins are not tradable.