Difficulty: Moderately Easy
Step1
Write a novel. If you have a computer, your Sim can spend the day working away on becoming the next Anne Rice or Stephen King. It takes time to finish a novel, however, so don't expect a payout until your Sim has put in 30 Sim hours on the project. The money your Sim receives for her novel is dependent upon her creativity skill.
Step2
Paint a painting. If you have the easel, you can click on it and have your Sim paint a painting. Once the painting is complete, you are given the option of selling it or hanging it on the wall. The price your Sim receives for his painting is dependent on his creativity skill. You can also choose to hang it on the wall for a few days and then sell it, as paintings can appreciate in value over time.
Step3
Harvest Simoleons from the money tree. If your Sim has acquired enough aspiration points for the money tree, you can place it in your home. Have your Sim water it a couple times per day and when it glows yellow, it is ready to be harvested. Click on the tree and select "Harvest Simoleons." Your Sim will gleefully pull bills off the tree and put them in her pocket. If her aspiration level is gold or higher at the time of harvest, she will pocket 40 Simoleons; if it is lower than gold, she will only get 1 Simoleon.
Step4
Use career reward objects to make items to sell. If your Sim has reached up to level 5 in the slack career track or level 6 in the culinary or science career track, he has earned reward objects that can help him earn money without having a current job. With the AquaGreen Hydroponic Garden—earned via the slacker career track—he can make plants that he can sell for Simoleons. The Schokolade 890 Chocolate Manufacturing Facility is available through the culinary career track, and your Sim can use it to make candy to sell. The Simsanto Inc. Biotech Station is acquired through the science career track and can be used to make and sell medicine.