The fastest way is fishing at the darmoon faire. On low population servers, the arena chest is also an option (50+ silver and items that are worth up to 3 gold in every chest)
If you need the money quickly and can't wait for a dungeon invite, farming and cooking meat is also an option. One stack sells for 60 silver afaik.
but the more important question is: How to spend the money? Imo that's really difficult if you are not in Halaa.