A lot of players like to forgo the Auction House when buying their materials and instead buy directly from other players. While you will be hard-pressed to find players selling materials such as ore and herbs through trade chat, it is possible to set up buying agreements with players who frequently farm ore and herbs.
Note
Watch out for players who are obvious botters; if they get caught, you can find yourself caught up in the trouble as well.
There are a few pros and cons of using a supplier for your materials instead of going through the Auction House. One of the largest advantages of using a dedicated supplier is that they will typically provide you with a guaranteed amount of the item on a set schedule and at a set price. If you rely solely on the Auction House for this, your supply can suffer from market fluctuations—leaving you on some days without any way to get your hands on the materials you need.
The downside is that you will have to negotiate a fixed price, which...