You should have "Wordpad" for free. Word itself is a product you buy.
Microsoft Office (of which Word is part) has traditionally been quite expensive for home users however Microsoft have started targeting them with "Home" editions which are more reasonably priced e.g.:
and you get the incredibly useful Excel and Powerpoint also.
Alternatively, take a look at openoffice which is a free alternative. It isn't Word but it can open Word files.