I only knew how to do word processing and some simple excel when I first started out. There are many tutorials on learning HTML coding. If you or someone you know is willing to spend 2-3 days on this, you can have a nice website up. Given what I know know, I can create a website in about a day if I have all the text already typed in by someone else. Yes, I highly recommend that you own one, but it doesn't need to be anything particularly powerful.
Modems are more important than the computer.
A 386 IBM or a mac running system 7 both are good enough. A color monitor is important and speakers are useful too. If you wish to put off the acquisition of a computer, you won't be able to receive email feedback from the Internet community, but you can still publish your telephone number on your WWW site. OneEarth and Institute for Global Communication are both Internet Presence Providers which work with computerless companies and organizations. I do not recommend this approach, but the option is available.