Sell low level crafted gears (find those golden items on MB); sell glamours; do maps and sell what you get from them (or craft stuff from it) and sometimes just find that item that sells for a decent price on MB but that you can get VERY cheap from vendors.
Pretty much how I make moneys without much effort... I sell glamour items like 1 in 2 weeks and do irregularly maps... gave to FC funds for buying a house a decent amount of gil and have since stopped donating (until we actually need the money) made back almost same amount which is 4 weeks.

Also easy money: Do your challenge log; dungeons; roulettes