I think you need CMS anyway, let me explain. In the future, if the site will be popular (I hope it will) and your client will want to add more features for the customers or modify the existing content, it will be a pain to modify something or add a new functionality.
We have had many clients who wanted to move their old static HTML site into CMS. As a result, client actually need to pay twice, firstly for creation of static site and then later when he/she want to move it to some CMS. So I think it will be more suitable for your client (and you too) to use CMS.
There are so many CMS on the market now, so I think there is no problem to chose a one suitable for you (for instance, Joomla or Wordpress).