Cheat:

     You could do a lot of damage with 256 missiles. Here's how to get
them.  Make sure you have no missiles whatsoever. Buy one missile. Fly
out  of the space station. Lock your ID on the space station but don't
fire.  Dock  with  the station and sell the missile. Fly out again and
press [M]. A line extends across the bottom of the screen and you have
256 missiles to shoot or sell.

2. Programming Cheat:

     For huge wodges of cash use a file editor to hack your saved game
file. Find sector 0 offset 136 and enter 40420F.