If you want a free alternatives of CMS as like WordPress than I've few name and I used some of them too.
Alternatives of WordPress :-
1) Tumblr.com : It is best and it's as like as WordPress.
2) Blogger.com : Powered By Google and It's free and easy to use.
3) Blog.com : It is not much popular like blogger and WordPress. But it's good.
4) LiveJournal : It's kind of journal. Here you put your post and others are read your post. It' not exactly like WordPress but good for beginer (Learner, Newbie in Blogging).
Hope all these are helpful to you. And you probably go with one of them.