Open the start menu, type "Farming," and open the Farming Simulator 2013 folder (Document, not file.)

Then, open one of the "savegame" folders, ex. savegame1 (Pick the one that you have started your game in.)

Open careerSavegame.xml with Notepad.

On the first line just after half way, it will say money="number"

Change this number to whatever you want. Remember, no commas.

For example, money="999999999"

Close and save.

Open the game and be rich!

Also, every time you save, it changes the number to your current amount. If it gets too low, just repeat the above steps.