I'd also like to mention that getting to learn the search option for the market wards will help you. NPC prices for gear are usually higher than player's retainers prices. Make yourself aware of what gear is optimal level for you as well. If you just search battlecraft > gladiator arm's > you'll see swords, for example. And you can see all the optimal levels for those weapons as you go down the list. You can do this with all the items/categories and I recommend looking through these before buying from an npc. However, look at things logically. Sometimes players can also try to overcharge for an item. Particularly for crafting ingredients that can be purchased from an npc. (Players will sometimes sell these items for just a little higher than the NPCs price, purposely, to try to trick people into buying from them.)

I hope I didn't overload you with this info, but I thought if I was still a bit new, this is info I'd like to know. =)