Bit of an edge case here, as I spent my time fishing and not fighting:
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Starting gil: 1500 (all I had available at the time) + no bait (10 gil each)
Ending gil: 1000 + 120 bait (10 gil each)

Activities: Fishing, Skyfishing, teleporting to Coerthas once
Time elapsed: Dunno, multiple hours.

Notes:
My final gil count is lower than my starting count, but I also repaired all my gear twice and had around 120 pieces of bait remaining, so I technically gained (as the 120 bait comes out to around 1200 gil). It's a tiny profit, though.

If I hadn't been skyfishing, I probably would've made around 3k gil, instead of 700 gil. Still mediocre for time spent, but it's a profit, not a loss.


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I wish I had a high level combat class to test all this argument about dungeons and FATEs not giving enough gil. There are so many differing accounts of whether you lose money or not.