Guild Merchants sell items that are specialized to the guild they belong to. (e.g. a bonecraft guild merchant will sell items that a bonecrafter would use.)
The pricing for Guild Merchants is not based on fame like most other merchants. It is based on the stock of their inventory.
- Guild Merchants keep stock in two ways. Every new day they re-stock a set number of new items of each type they usually stock. This stocking is cumulative. For example, say they re-stock 3 of Item-X everyday, and started yesterday day with 0. Today they sold 2 after re-stocking. Tomorrow they will have 4. Because of this, items can be sold out.
- Additionally, they will sell any items sold to them by players. They only buy items that are relevant to their Guild though.
- The price of the item is dependent upon the demand for it. If the item sells out everyday, the price they charge will go up until it reaches the maximum. If it doesn't sell at all for days, the price will drop to the minimum.
- Finally, the guild will only stock a certain amount. It will never have more than some fixed amount of each item available. If you try to sell more of an item to the guild than they will stock, it just won't let you sell it anymore.
Note that Tenshodo Merchants operate the same way that Guild Merchants do, provided that you are a member of the Tenshodo. If you are not a member, then they will only speak to you like a normal NPC rather than react like a Guild Merchant.
Guilds are not open all hours of the day. Each guild has specific "hours of operation" during which they're open - typically they're open during the day and closed at night. The hours they are open vary from guild to guild. In addition, each guild has a weekly holiday during which the shop is closed for the whole day. Which day it is varies from guild to guild as well.