There are no Sims games that you can legally play for free. And you should pay for them if you want to play; a lot of people put a lot of time and effort into creating those games, and they should be compensated. Of course, people will always pirate software (and if you want to know how to do that, I suggest you ask elsewhere – I don’t think the mods would like us teaching others how to do illegal things.)
Similarly I don’t know any other free life-simulation games out there that are on the same caliber as the Sims, since they’re pretty complex. I did a quick search for “flash life simulation game” and the first hit was this game called MicroLife. I don’t know how good it is, but hey, it’s free.