Pushing narcotics is just startup peanuts compared to what the Black Market stations and shipyards really have to offer.
WARNING: POSSIBLE SPOILERS
If you're not in a hurry with your game the Shipyards have
unlimited funds for
military items up to 100K sales value per unit. Hunting Dwarg behemoths or Earth Slavers can net you over a million relatively early if you farm the reinforcements as the Shipyards and Stations pay a premium for faction military items (those +NotForSale that Commonwealth buys at 10% value).
Also, if you hoard Heliotrope fuel or have Ingenuity, you can upgrade to NX250 reactors at the Shipyard and have a 10%-chance to enhance them for 50% profit. You just need a decent starting capital, as you have to sell them all at once, and a spare 150MW reactor to reinstall and upgrade each time.
... And lots of time, which you can kill by recharging solars over a sun or hunting enemy reinforcements, bringing you full circle.
Black market stations are good for spending that cash so you can rise through the Syndicate ranks and get some decent gear. Hint (like
ThePrivateer said): only your purchases count, sou you can buy, sell, re-buy, re-sell ... and, as long as you have cash - buy your way to the top just like a real gangster.
Just watch out if you follow this method, that you don't get hooked
