You may have heard the term Bravemart... all this refers to is two merchants who are standing side by side in Braverock. The benefit is that if you click on one merchant and they are not selling what you need you can click on the second one, then if that one doesn't have what you are looking for the first will have different items when you click on him again. Essentially you can click on them back and forth forever and each time they will have new items so eventually they are bound to have what you are looking for, this can also be a very good way to take advantage if you have a high trading skill.

The only drawback is that you have to complete a quest for the one standing between the stands to open up for business. It is a very quick quest though so it isn't too much of a hassle. The quest is called Goods Messenger and the tutorial for it can be found HERE.