There are no versions of "The Sims" series that you can play for free from a computer. However, there is a free version which can be played from many mobile devices or smartphones, titled "The Sims FreePlay".
Although it is no longer available, Electronic Arts did briefly release a free "The Sims" title called "The Sims Social" that was playable from a Web browser via Facebook. "The Sims Social" was first made available for play in 2011. Two years later, in 2013, Electronic Arts announced that they were shutting down the game due to dwindling player numbers and lack of activity.