Depends on what you're trying to do.
If you after a cheap webpage, most low-end webhosting services will have some kind of free, usually web based, WYSIWYG type editor. I know Comcast does this, and Yahoo/Geocities both used to offer something like that (I haven't looked since the 90s).
If you want to really build professional looking websites, you're probably going to want Dreamweaver. You're also going to need to learn some HTML, CSS, javascript, and some serverside scripting language (php, asp.net, etc.). Cheap WYSIWYG type editors suck, and good WYSIWYG editors don't work well unless you have a good understanding of the underlying technologies.
EDIT: Personally I use Notepad++ for most of my web-work, and then firebug and IE8's dev tools for debugging client side scripting issues.