Characters have both a ranged weapon slot and a slot for ammunition. While some classes have items that go into the ranged slot that do not use ammo, bullets or arrows are required to fire bows, crossbows, or guns. It should be noted that both bows and crossbows use standard arrows; there are no crossbow bolts.
Of the three classes that can use these weapon types, rogues and warriors will usually be content carrying one or two stacks of ammunition, since it stacks to 200 and is sold that way. While each shot does consume an arrow or bullet, rogues and warriors rarely use more than 2 arrows to initiate a fight. Since their concern is more in getting the attention of their enemies rather than actually dealing damage, any basic ammunition is fine.
Hunters, however, rely on their ranged weapon damage, and ranged weapons typically have lower damage output than melee weapons because the ammunition adds to that damage. For hunters, having good ammunition is important, and is the primary recurring cost for the class beyond basic repairs. Hunters will typically carry a quiver to get a haste bonus, and sometimes find that these specialized containers do not hold enough arrows for a prolonged excursion out of time.
While most arrows are bought from vendors, either normal vendors or sometimes specialized, as noted below, it should also be stated that engineers can make bullets. With the exception of Thorium Headed Arrows, which are the result of a quest turn-in with the crafted Thorium Shells, (quest,) engineering cannot make any arrows. Engineering also makes guns, so this is not wholly surprising.
Basic ammunition becomes available from General Supply vendors at various levels:
|Level||DPS||Arrow name||Bullet name|
|1||1.5||Rough Arrow||Light Shot|
|10||3.5||Sharp Arrow||Heavy Shot|
|25||7.5||Razor Arrow||Solid Shot|
|40||13.0||Jagged Arrow||Accurate Slugs|
|55||22.0||Blackflight Arrow||Impact Shot|
|65||32.0||Blackflight Arrow||Ironbite Shell|
|9.5||Desolace Quest||Stealing Supplies||Feathered Arrow||Exploding Shot|
|11.5||Drop: Baelog||level 35||Precision Arrow||-|
|12.5||Engineering||level 37||-||Hi-Impact Mithril Slugs|
|15.0||Engineering||level 44||-||Mithril Gyro-Shot|
|16.5||Alterac Valley||honored rep||Ice-Threaded Arrow||Ice-Threaded Bullet|
|18.0||Drop: Lord Roccor||level 47||-||Rockshard Pellets|
|20.0||Drop: Shadow Hunter Vosh'gajin||level 54||Doomshot||-|
|27.0||Engineering||level 57||-||Fel Iron Shells|
|26.0||Cenarion Expedition||Honored rep||Scout's Arrow||-|
|34.0||Halaa||control of Halaa||Halaani Razorshaft||Halaani Grimshot|
|37.0||Cenarion Expedition||Revered rep, level 68||Warden's Arrow||-|
|42.0||Engineering||level 62||Adamantite Stinger||Adamantite Shells|
|46.5||The Violet Eye||Revered rep||Mysterious Arrow||Mysterious Shell|
|53.0||The Scale of the Sands||Honored rep||Timeless Arrow||Timeless Shell|