Best money method early on is to grind the jobs system or beg for money to get a hauler, drive out the asteroid belt, and mine valuable ores and ignore the low value ores, then return to the station to sell the ores. If you get lucky and find the most valuable ores, you can pay back the cost of your ship after a single mining run. Otherwise it will take 3-4 runs to pay for your ship, with each run lasting 20-40 minutes.
Balance is a work in progress of course, and subject to change.
I strongly suspect that at some point a player will design something that is cheaper than the hauler, but still good enough to be more profitable to mine with than the default mining jobs.
Late game money making basically revolves around building a giant version of the hauler. Some people have experimented with cargo locks and asteroid hauling, but those systems are riskier, bulkier, and less efficient - albeit fun to work with. Mining also gets much faster and more efficient when multiple players work together.