Buy the Atlantian Monument by building a school. Build it then construct a warehouse. Finally, build the Atlantian Treasury and fast forward the game so you get 80 Atlantis Crystals. Sell them to the highest bidder to get about 5,000 gold
Start any single mission and immediately save the game. Quit the game. Use a text editor to edit the "*.save" file that corresponds to that game session in the "save_game'" folder in the game directory. Find the line "[COLONY_GENERAL_DATA]". There should be some digits after that. The format of the numbers should resemble:
Change the second number to any value desired. It is the amount of money given to you for the mission. For example, change "43900.000000" to "4390000.00000".