I found a Gauss Rifle for sale in my starting location

[Marauder3D]

I accidentally clicked no on that black market event: warning to everyone, it hasn’t popped again!

 

[Beric]

I started a new campaign, and got access very early on. All you have to do is be in good with the pirate faction, and at some point you will get a event that asks if you want to pay a membership fee to get access to the black markets. What you pay will be tied to your reputation with the pirates. After that, the star map will be market with icons denoting the planets with black markets.

I found it convenient to stick to pirate missions where the opposing force was Capellans, Directorate, Taurians or local government, and avoid missions with anyone else where the opfor is pirates. Yes, you miss out on a lot of juicy missions, but that's all part of the trade-off for the access.

The pirates hate my guts. No chance of getting the event?

 

[Donvale]

The pirates hate my guts. No chance of getting the event?

You will get it, but it will just cost a lot more to accept, like 5 times as much compared to if you were nuetral.

 

[SpenReyn]

I accidentally clicked no on that black market event: warning to everyone, it hasn’t popped again!

Kiva said on the live stream that the Ally and black market events WILL happen again later if you say no, it's just a random amount of time.

 

[BunglingLummox]

Did you take a crit on one in a mission?

No. And I got ammo too.

 

[Panzer-Killer]

The Black Markets appear to have pretty much everything valid. I have a whole SLDF Highlander for sale in the Black Market of my current system, but at 24,000,000 credits not much chance of stretching my meager finances to even get close to it! (I only have about 4,000,000 credits).

well, 24,000,000 C-Bills would be a total no-go for me too, even though I'm currently in post-Arano Restoration campaign, with funds amounting to about 27m C-Bills - that would mean too little cash remaining if I bought it, with current expenses in the range of 1.4m C-Bills/month...

 

[Panzer-Killer]

I have the dual Gauss (a flashpoint bagged me a second). Now I just need the KGC-0000.

I'm lucky enough to have as much as three of them since last night, the SLDF Highlander HGN-732B's one, received during the Arano Restoration campaign, as well as two more (which I got from the Criminal Minds Flashpoint)!

EDIT: I got the two extra Gauss Rifles as Reward for successfully completing decision-branch B of "Headhunting" Flashpoint, not for the "Criminal Minds" one (that one netted me a completely different, but juicy nonetheless, LosTech reward:

Spoiler

a complete pristine SLDF Griffin GRF-4N 'Mech, configured with an ER PPC two SRM6, as well as full Heat Sink (D) & JJ (S) sets

 

[BunglingLummox]

I'm lucky enough to have as much as three of them since last night, the SLDF Highlander HGN-732B's one, received during the Arano Restoration campaign, as well as two more (which I got from the Criminal Minds Flashpoint)!

Ohhh, that gives two? That'll be where my mystery third came from, then.

 

[Prussian Havoc]

I accidentally clicked no on that black market event: warning to everyone, it hasn’t popped again!

Black Market Access was offered to me twice. Both times it would have cost 2.5m Cbills. It just didn’t sit with how I wanted to role play this first Career Mode attempt so I passed up on it both times. : )