There is a pretty good spot to get some good cash early, even more so if you manipulate the RNG. There is a chest in Yensa Sandsea - Trail of Fading Warmth that yields up to 11,000 GIL. I average around 9k-ish per pot via the RNG method. Below is the information you would need to manipulate the RNG to spawn the pot, and then what line it falls on to get the most gil out of it. I have a thread I was working on that goes into more detail on this topic. Unfortunately my PC died and I have put the project on hold. If you wish to read what I have started (which isn't much) please go here:
-Yensa Sandsea - Trail of Fading Warmth Chest Number - #41 Contents - 11,000 Gil Max - Repeatable Chance to spawn - 10% Chance for Gil - 10% Connecting Zone - Nam-Yensa Sandsea - Demesne of the Sandqueen First time entering this zone RNG Moves - 4 Lines Chests Line - 2 One time only chests, if any, are removed Not applicable, Remains the same
Hope this helps, and sorry for the delay in the reply. Also thank you to ZekuMusashi for answering the question that Spiroth_Kweehh had asked.
Enjoy, Tirpitz --- Final Fantasy XII: International Zodiac Job System Maps- http://www.fftogether.com/forum/index.php?topic=2764.0
Also forgot to mention there is another good cash maker chest in Stilshrine of Miriam - Ward of Velitation. It has a max of 65,000 Gil, repeatable. Though the chance is horrible low, 5% to spawn, and 5% to get Gil. Another chest you would probably want to work the RNG to get the most bang for your buck. I didn't get that far in my RNG spawning project to get the particulars of this chest though unfortunately. Though it would be easy to crack since there are only 2 possible chests in this zone after you get the one-time-only chest that contains "Countdown". I would wager that the RNG only moves around 5-6 lines at most per zone.
Also, once you get a few Cat-Eared Hoods, you will never worry about Gil again. You can get it pretty early via the Bazaar if you know what mobs drop the stuff you need. That FAQ FF12GM made for earliest Bazaar stuff could tell you what, where, and when. IIRC you also can buy them from the Clan outfitter in the Muthru Bazaar after a set amount of hunts, the number eludes me at the moment though....
Anyway hope this helps, Tirpitz --- Final Fantasy XII: International Zodiac Job System Maps- http://www.fftogether.com/forum/index.php?topic=2764.0