The prices at the black market are extremely high (often topping 600creds/100 unit resource). In addition, the sell prices do not fluctuate, usually staying at 250 then dropping to 200 in the middle of the game.

Is this intentional? I'd like to see a system where if you sell a bunch of metal and flood the market the price actually goes down, as right now I'll put a ton of creds into metal mining, (which also isn't a giant black hole if you play a long enough game), then sell it as it's used very little in ship production.