Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding is recommended. With a text editor, edit the "initialpref.lua" file in the scenario or level folder in the "scripts" directory in the game folder. Near the top should be the following entry:
if Game.GetDifficulty() == DIFFICULTY_(difficulty) then InitialValue.playermoney = (money to start with);
Find the difficulty you are playing under and change the initial value to whatever desired. Note: The custom scenarios in the game are in the "custom/deepred" folder.