Getting Gil Through Marketplace Help?

[Niwashi]

I personally prefer to gather just one thing to sell, because my inventory, retainers, and chocobo saddle are very full.

In that case, intermediate crafting materials (leather, ingots, cloth, etc) are a good bet, especially if you can make them High Quality. They also have an advantage that demand is a bit more consistent than for gear which sells a few pieces now and then, but it's harder to sell in bulk (though when it does sell, some of it fetches a significantly better price than mats, so there's a bit of a tradeoff).

If you go with mats, the main thing to consider at your level is that NPC vendors will be undercutting the really low level ones (to roughly level 15 or so). To make money selling materials, you need to offer ones high enough in level that NPCs don't sell it. The recent update to show NPC sell price in item tooltips should help you figure out which are viable. You can make some money selling things like Aldgoat Leather (LTW 17) or Mudstone Whetstone (GSM 20), but for Brass Ingots (GSM 14) for instance you'd be competing against NPCs that offer it for 68 gil.

[CryBloodwing]

In that case, intermediate crafting materials (leather, ingots, cloth, etc) are a good bet, especially if you can make them High Quality. They also have an advantage that demand is a bit more consistent than for gear which sells a few pieces now and then, but it's harder to sell in bulk (though when it does sell, some of it fetches a significantly better price than mats, so there's a bit of a tradeoff).

If you go with mats, the main thing to consider at your level is that NPC vendors will be undercutting the really low level ones (to roughly level 15 or so). To make money selling materials, you need to offer ones high enough in level that NPCs don't sell it. The recent update to show NPC sell price in item tooltips should help you figure out which are viable. You can make some money selling things like Aldgoat Leather (LTW 17) or Mudstone Whetstone (GSM 20), but for Brass Ingots (GSM 14) for instance you'd be competing against NPCs that offer it for 68 gil.

Aldgoat Leather is going very well. 50 for about 45,000.