Stick an Autominer on an Erudite vein (the green ore in forests), put a Refinery nearby, slap a Receiver on the red side and a Delivery Cannon on the green side. Soon you'll have more money than you can spend.
This, combined with Payload Terminals, is what makes the endgame so boring. When you have all five terminals and infinite bucks, from that point on the Campaign Mode is basically Creative Mode with manual purchase of blocks. Why bother with anything when almost everything in the game is literally a single click away? (Except RR stuff, they are impractical anyway.)