These are not traditional cheat codes, but they do influence the game in a similar way.
You can stop your Sims from aging without cheating. In the options menu simply uncheck the Aging box. Use the Lifetime slider to slow down the aging process, making a potentially longer (or shorter) game for your Sims.
Use the options to 'legally' stop your Sims from aging or slow the process down
Anything you buy can be resold on the same day for the price you paid for it. As long as you have the cash to begin with, you can effectively 'borrow' items, use them, for reasons such as to upgrade your Sim or make them happy, and then sell them before 24 hours is up with no loss of value. Good for party items!
Of sorts. To remove the risk of dying, procure for yourself a Death Flower. You can find at least one from the graveyard near it's entrance in a bush. As long as your Sim has it in their inventory, the Grim Reaper will not harvest your soul. You can also find 'Unknown seeds' in the graveyard to allow you to reproduce the flower in your garden, and you must find alternative means of getting the flower after one tangle with the Reaper.
If any cheats do not at first work, try activating testingcheatsenabled true before entering them. While every effort has been made to test all of the above cheats to ensure they are reported accurately here, the above technique should solve any possible errors.
Added by: Sanzano Jun 15th 2009, ID#14040