Virtuoso Inking Set

The Virtuoso Inking Set is mandatory for all those pursuing the primary profession of Inscription.

Source
Bought from the following vendors for (less faction discounts, hence with your home faction, when you start out a character this will set you back ). Unfortunately, in relation to other professions, this is the "hardest" to get going, as with the exception of and, they are not available to acquire in the starting zones. They can be mailed from an alt character, or otherwise the easiest locations to acquire them are:

Alliance

 * - Elwynn Forest has no sellers. The nearest vendor is  in Stormwind City
 * - Dun Morogh has no sellers. The nearest vendor is  in Ironforge
 * - Teldrassil has no sellers. The nearest vendor is  in Darnassus
 * - Dun Morogh has no sellers. The nearest vendor is  in Ironforge
 * - on Azuremyst Isle
 * - There are no sellers in the phased area of Gilneas, the nearest vendor is in Darnassus once you come out of the phased zone.

Horde

 * - Durotar has no sellers. The nearest vendor is  in Orgrimmar
 * - Tirisfal Glades has no sellers. The nearest vendor is  in Silverpine Forest
 * - Durotar has no sellers. The nearest vendor is  in Orgrimmar
 * - Mulgore has no sellers. The nearest vendor is  in Thunder Bluff
 * - Eversong Woods has no sellers. The nearest vendor is  in Silvermoon City
 * - from

Other locations
In addition to the above locations, as well as all the cities, there are sellers in: Kalimdor Eastern Kingdoms Outland Northrend
 * Bloodmyst Isle
 * Darkshore
 * Dustwallow Marsh
 * Azshara
 * Northern Barrens
 * Felwood
 * Uldum
 * Blasted Lands
 * Loch Modan
 * Westfall
 * Ghostlands
 * Silverpine Forest
 * Twilight Highlands
 * Shattrath City
 * Hellfire Peninsula
 * Dalaran
 * Borean Tundra
 * Howling Fjord
 * Icecrown


 * Garrison

Battlegrounds
 * Alterac Valley