A yellow rock would cost 6,328 for my rank 0 bastokan mule. I'm surprised it's so much more expensive than the price listed here. I know rank influences price, but I didn't think it varied more than about 20%.
This is a guild merchant, so it is supply/demand rather than fame that affects the price. The guild price range used to be 2:1 (cheapest:most expensive), but last year they changed it to 5:1. This was probably due to the fact that people camped the guild to buy items even at the 2x price. At 5x, the commonly purchased items are no longer a steal, but they also are no longer "stolen".
So for any item that you see at a guild merchant, if the range is a 2:1 range, to be safe assume that it may be as much as 2,5x the highest listed price here.
Note that the prices of ores go up the next day if they sell out or sell well the day before, and also if someone sells that ore to the guild, it will cause the price to go down slightly (which can be cancelled out if the ore is bought out completely anyway).
The availability of equipment depends on whether or not someone sells that piece to the guild the day before. If someone sells only 1 piece, the price will be very high the next day. If someone sold several pieces, the price would be lower (I assume, because no one really sells ten chain gorgets to the guild for 2000g)
I do not see a "garnet" listed on this list. I went all the way to the Goldsmith's guild to buy a garnet. It turns out it is only a HQ synth. So, it needs to be taken off the garnet info page. I was trying to find a cheap way to obtain one for the quest on the headstone in Yhoat for ZM5. I guess I'll turn 20k (current Jeuno AH price) for a garnet, into 80-100k for Opo-opo necklace.
If guild merchants are like other NPC vendors, their stock may be in fact be related to their home nation's current conquest standing, and whether or not you are a citizen of the same nation as the merchant (some scrolls, for example, are only available in the magic shop of the ruling country, and sometimes only if you are a citizen of that nation will you be able to buy it). Perhaps if you're a Bastokan in first place, you'll see all of the above. That hasn't happened on Seraph in a long while, so I have no way of verifying the list. From personal experience, however, I have seen materials sometimes appear on guild stock lists that I rarely saw before, so there is definitely an unknown variable at work.
Guild merchants work differently then all other merchants in the game, The list above are all the items this guild merchant will possibly sell to you, the guild merchant will only sell those however, if a player first sells one to him. He doesen't have an unlimited supply of items like other merchants.
Are chain gorgets sold only on certain days? Im browsing the guild wares on a Lightningday, and Chain Gorgets are most definitely not in stock. Ive checked every AH on Remora: zero chain gorgets.
When it is WIndsday, the guild prices drop a lot for most of the common popular items. If you want cheap prices and don't wanna wait for AH to resupply, then buy materials on windsday only.
Prices for copper ore ranges from as low as 12 to 20. I usually see it at 18. Silver ores range from as low as 315, and I've seen it go as high as 630. I usually see it aroun 350-420. I've seen Mythril ore sell between 1500 to 2240, but I don't check it too much as AH is cheaper. Zinc ores sometimes appears (I know know when) for around 250.
Ok, so one day I go in and the prices are super low, crazy prices, really. So, I run to my mog house to get more gil and go back, the prices went back to normal! AH! What's up with that? Periodically I go back and check. I've never seen the amazing prices again.../sigh... Anybody notice this too? Or, did I have a brief moment of insanity? Cuz' ya know, that does happen sometimes...