I totally disagree with it being OK to update by hand for your first site, because the longer you leave it, the more of a pain it will be to make the switch. It will almost certainly entail re-uploading all your content and entering in all the information / text etc.
If you're planning to seriously get into the paysite market, I would strongly suggest you get a CMS right from the word go and use the time you'll save on more marketing
