It depends on why you want it. My Heritage Family Tree Builder is free and I find very good for charts and reports.
As an alternative, you could use the free options Genes Reunited or Ancestry websites. I use Ancestry to store my tree and you have the option to easily share your tree with others but still making it completely private to everyone else - doing this is often easier than emailing someone a Gedcom. However, Ancestry still gives you the option to download a Gedcom copy of your tree if you wish to change software later (I don't think Genes Reunited gives you this option). Also, Ancestry members can search for their ancestor and if he/she is on your tree, they can contact you, without you spending a penny. I know lots of people like to use Family Tree Maker which syncs with Ancestry - but this is a piece of software you have to pay for.
Basically, I just wanted to put this on to show you don't have to necessarily have a tree offline - everything can be online and, particularly the Ancestry version, gives you lots of options to add events, sources and relatives easily. Then, if you need to make a chart or report, you can easily download your tree and import it into My Heritage. I've been researching for nearly 2 years now, and I've never needed a piece of software on my computer to make my tree.
Jack
