@ SCC: If I go for a single bounty, then return to town, then much the earnings is spent on replenishing supplies and fuel consumed. Assuming nothing went wrong and I have all of my ships and weapons, I have a modest profit, maybe enough to buy a small ship or to outfit the new acquisition recovered from battle. Not really enough to upgrade or expand comfortably. However, it may be a better idea to leave that profit unspent as a cushion for setbacks. However, it is not sustainable if the bounties upgrade faster than I can keep up.
One point in the midgame, bounties were starting to outpace my fleet, and it was a razor's edge between survival and ruin. I had to do a few exploration missions to get more of a money cushion before I resumed bounty hunting. Things got better when I recovered my first Legion, then an Astral soon after.
One time, I tried to use a smaller fleet to match the enemy instead of bigger fleets. I lost ships and it was simply more profitable in the long run to overwhelm the enemy with more and/or bigger ships (especially when my ships are unskilled zombie clunkers and theirs are often not) and suffer maybe one or two casualties every few fights.
P.S. Harvesting system resources (like abandoned stations and derelicts) only works once. Once harvested, they are gone. I often visit the same systems repeatedly for bounties, who just cannot stop spawning there. One time, I had new bounty pop out of thin air seconds after I killed the bounty living next to the planet, and I smashed that one too. Bounties are the perpetual gift that keeps on giving.