Props are the objects that are used to decorate the stage where Sims perform in The Sims 3: Showtime. It is mainly used by Sims who work in Magician, Acrobat, and Singer professions. Props are essential in order to build up a performance scoring when Sims perform a gig, and the score would be higher if they set up the stage with props of the same style. Props can also be used as a decorative object at home, which can be found under "Props" category in the Buy mode.
Upon performing a gig, Sims can set up the stage using the venue's setup, custom setup, or previously saved setup. Choosing custom setup will bring up Buy mode and allows the players to decorate the stage by buying the available stage props and FX lights or using the existing ones in the family inventory. After that, the game prompts the players whether they want to save the customized setup or not. Keep in mind though, as customizing the stage will erase the venue's default setup. After Sims are done performing, all props and FX lights are placed in the family inventory.
By default, only several stage props are available in the game for Sims to buy. Players need to use SimPort in order to unlock more stage props as well as costumes. In addition to stage props and FX lights, Sims can also place the Hypnotizer, a premium content from The Sims 3 Store, and Singer and Magician magic gnomes.