The following cheat seems to work:
Save the game on turn 1.
Remember the cash balance.
Convert this to hex.
Hex Edit the save game file with
a Hex Editor.
Edit/Find the name of your country
e.g.: Deneb
Somewhere 79 to 82 bytes after
the name is a halfword (2 bytes) containing the hex value of
your cash change it as you wish.
A shortcut is to use UGE to find
the numeric value of your cash and look at the displacement
address. You can use UGE to change it directly.