Corona

Your first fighter. Very weak and also cheap as hell. All you need is the smallest base, which has no resource cost, and about four of the smallest mines, which also has no resource cost. Then you extract oil and iron which exist almost everywhere on every planet. Then you build a small factory and start pumping out thease. You can´t build them as fast as you extract the resources so you will get an endless amount of them :).

Build Cost: 5 Iron, 2 Oil, 25 Credits