Guild Storage is a feature of Guilds that is unlocked when the Guild has at least 20 members.
Guild Storage uses it's own set of Storage Chests, which must be purchased with NX. One Storage Chest costs 7,900 NX. There can be a total of 21 Storage Chests in a Guild Storage.
 General Usage
Guild Storage allows allows anyone of the same guild to share items. This avoids mailing fees with the Mailbox, and can be used to quickly share multiple items instantly.
The Guild Storage can also hold up to 10 million gold.
The Guild Master can set restrictions on what each member rank can access with the Guild Storage. Restrictions include withdrawing or depositing gold or items.
The Guild Storage in Colhen is located at the Northwest corner of the Inn.
The Guild Storage in Rocheste is located between the Marketplace Message Board and the Beggar. It sits besides the Goldsmithing Expertise Stand.
The Guild Storage in Malina is located outside of the White Whale Inn.