Your CMDR needs to stay alive, so he/she needs to eat. Why not add a food fee to keep your CMDR alive. Of course, for noobs, the Pilot's Federation would provide free ration packs. For explorers, a farm module could provide food, if you mined or prospected all the phosphourus and all the other stuff plants need. You could make water by fuel scooping oxygen from atmospheric planets and mixing it with the hydrogen from stars.