Materials ('mats') - items that get used in professions. This is driven more by use than by source; for example, copper is very easy to mine, but it is widely in demand, and you can often find bargains in copper, bargains you can profit from. Contrarily, some very scarce mats may have low demand, may only be used in one mediocre recipe, and may not sell.
Elixirs serve the same purpose as Flasks, but the buff expires if you die. You'll only use these between 1-70, generally speaking, until you can start buying Flasks which persist through death. Try not to die, and carry extras just in case. If you can't find an Elixir with the stat you want, look under scrolls, since they count as battle or guardian buffs as well.
EXPLORE TWO FABLED KINGDOMS – As a champion of the Horde, travel to Zandalar to persuade the trolls to lend their naval might to the war effort. As a defender of the Alliance, sail to the seafaring kingdom of Kul Tiras, home of Jaina Proudmoore, and rally its inhabitants to fight for your cause. Once you’ve successfully recruited one of these proud kingdoms to your faction, infiltrate the enemy’s newly claimed territory.
As you're leveling, I generally recommend you just follow the natural flow of the progression through each zone. They're laid out fairly reasonably. But don't be afraid to hop around, especially if you're near a quest objective. You shouldn't actually need ALL of the zones listed to reach 62. Pick the ones you like best. It's much more important to simply be as focused as possible and flow from one quest to the next.
To use it as a bank, figure out how much you want to have on-hand on your character based on how much you normally spend on repairs, food, ammo, etc. and send the rest to the bank alt. The principle here is "Out of sight, out of mind.". Money "you don't have" cannot be spent, requiring you to log out of your character, and then to log into the alt.
Note that the previous method to obtain the tome has been hotfixed and no longer works. Initially, discord user Darethius#8990 has obtained the tome one week ago accidentally by hearthing during the Zul encounter in Uldir on Heroic difficulty. This was unintended and was quickly fixed by the devs. As stated above, to get the tome you now have to kill Zul on Normal, Heroic or Mythic difficulty!
Now that we have a lot to post we reached a point where we have to plan what items we post on an 12-24-48 hour cycle. The auction house fees for Warlords of Draenor items are extremely high. And the values of the items are really screwed up. A lot of the weapons or armor has an item value of 5-10.000 Gold. But they look plain bad and the chances of selling them is pretty low.