Easiest way to make money, is to hang out at the hub, and someone will likely gift you products worth several million each to sell.

I also preordered, but I played long enough to amass some credits, and then learned how to dupe items, so money hasn't been an issue for a long time. It definitely makes it easier to come back to when you have a few billion credits.

Still, I think I've only got a couple hundred hours played. I want something to fight with my ship I spent hours upgrading (actually fight, not pathetic 1 shot sentinels). I don't get why they allow you to build such powerful ships, with literally nothing to use them against.