Norfleet
it's the sheer quantity of shite that you're selling.
BOMBARD missions. Prisoners and commodities (prisoner missions reward dil, hence the demand)
DISABLE FREIGHTER: Contraband, prisoners.
HAGGLE: Rare commodities, jevonite, lockets, leaves etc. Sell that shit.
PILLAGE: prisoners, contraband, and gear (vendor for anywhere between a few k to 40k)
SCAVENGE MINEFIELD: Commodities, vendor fodder.
These missions depend on your doffs, critical successes reward more, things like dosi rotgut (200k min from what i've seen) particle traces (some i've sold for 100k plus).
Use story missions to transwarp around the map (this will be your only expense)
You'll need weapon doffs (torps, energy etc, these are the big ones.
Tractor doffs.(for freighters, again big money makers)
Assault squad doffs.(bombard and on planet missions)
Transporter doffs.
Traders and quartermasters (haggle iirc)
Explosives doffs. (minefields)
I think that's all, barely have time for an hour a day at this game currently (too much to catch up on). So the doffin' is ideal.