-The annoying flies are actually worth something. Enable the move_objects on code. When flies enter your home, go into buy mode, select the flies, and delete them for 468 simolians.
-Purchase a volleyball court. Enable the move_objects on code. While your Sims play, they will drop the ball, and you can sell it. This will not keep your Sims from playing, as another ball will appear.
-Purchase as many snow blocks as you can fit in your yard. Wait a day, then sell them. This will earn a profit because the cost 25 Simoleons and will sell for 53 Simoleons.