Inspired by the weird-ass conversation in the "Interesting Sales" tread.
Here is a screen-shot of the directive weapons list for Black camo:
* SMG-46G Armistice
- Golden SMG part of a retail-DVD you purchase from gaming stores if available near you. Gave some boosts, some Station-cash and a golden version of the 1st generation SMG's of all empires. May or may not be available at this time because this is something I bought before Sony Online Entertainment became Daybreak Games Company.* NS-15M AE and NS Baron G5AE
- Black and Orange special edition versions of NS LMG and shotgun that came out about a year or so ago. Costs cash IIRC and I am not sure why it was available or when it will be around again.* NS-11P
- Platinum version of NS Assault Rifle. Acquired for free by entering a code in-game during a specific period that unlocked it for the character (not sure if account-wide) you were on at the time.* T7 Mini-Chaingun AE and NS-44 Commissioner AE
- 3-year anniversary bundle that granted a faction-flavored NS-44 and a re-skinned Heavy Weapon for all factions. It is highly unlikely these will be around at the 4th anniversary as it is likely different things will be in the 4th anniversary bundle.* Hexedge
- special knife. I don't recall when or how this weapon was acquired, it's been a long while now and I never used it.* Heartstring and Blackheart
- two special versions of the Hunter CQX crossbow that is available for single purchase around valentines, IIRC. Expensive A.F though.* Various different flare guns
that come around during different times. IIRC the Patriot version unlocks for purchase every 4th of July, I don't know about the Triumph versions.* NS-15 Gallows
- perhaps the single most annoying to get and potentially most expensive weapon in the game, the Gallows require you to complete the bounty hunter directive.* NS-357P Underboss, NS-11CP and NS-15MP
- Platinum versions of the NS LMG, Carbine and rapid-fire revolvers, STILL AVAILABLE AT THE MAKING OF THIS POST. These are some of the least outlandish, relatively inexpensive weapon on the whole list, best of all one single purchase will get you 3 out of 5 required weapons. If you are not opposed to using IRL money to get your black camo I strongly suggest you buy these as the price per weapon average to less than the black/gold versions of them and they are far more user-friendly than auraxing, say, a few flare guns.
I will end the list here because I don't know enough about the rest of the weapons in this list to comment. Suffice to say, all of these come around at rare times, some are far harder to aurax than others, and the one's that are 'free' in the sense that they won't cost you any IRL cash are extremely few and far between. Indeed outside of the Platinum NS Assault Rifle I don't know a single one that I know for sure costs no money. If you wish to get Black camo while spending no money at all you may have to wait several years depending on how vigilant you are for the opportunities to come about and what weapons are available when and how.
Everyone else feel free to comment and most of all, fill in this list with info if you have anything to share regarding any of these. I would especially welcome any info on what weapons cost money or not, and when/how to get them, to help Arrows with way more patience than money.