The Maxis classic is completely free on Origin for a limited time.
All you have to do is head on over to the On the House page, and click 'Get it Now'. If you don't have an Origin account, just create one, it's free, and then you'll own a copy of SimCity 2000. Hoorah!
Sim City 2000 was first released back in 1994 for computers running the Mac OS, and was later released in 1995 for other systems. If you want to relive your childhood, go ahead and download it, it's only about 80Mb. And even if you've never played it before, you should try it out, it's a great game.