IMO, they just need to make monsters drop gold, simple as that. Not a crazy amount, but probably between 25-75 from 1-30 (monster level), 100 to 200 from 31 to 40 (monster level) and 210 to 250 from 41 to 50 (monster level).

Mind you, these are probably abused, but it's just an idea, and if you were in a party, the gil would split with the amount of player that are present on the same map