MySims

MySims cheat codes: 
Modify Savegame: Unlimited items:
First, play the game and grab HAPPY essence (because it is easy to obtain)
or APPLE (because it is the first essence), then save. Go to My Documents
folder -> Electronic Arts -> Mysims -> SaveData1 (can be 1,2,3 according
the savegame number). Open "playerRecord.xml" with a text editor such as
Notepad.

Find the line:
[happy type="number"] (or [applefruit type="number"] )

In this line you can edit the number of essense (up to 99) for example:

[happy type="number"]99[/happy]
[applefruit type="number"]99[/applefruit]