hmm... the most common way is to make more accounts, and set them on remote attack and remote walk at kelan cave. If you do this over-night, this will earn you lots of ores to sell to NPC or players.

You can also make some vehicles to sell, like plane or steamship, they are quite popular.

If you have good alchemy, compound some good equip, like bows or armour, and sell them.

or you can ask the owner of the King's gown, and see if he/she would agree on something other than money... like trade him/her some armours...