Joomla - Adding visitor comments function

I currently have a travel site using Joomla. It is not set up as a blog but I would like to have the option for people to add comments on some articles as if it WAS a blog.

I do NOT want to go through the hassle of changing the site, moving it over onto a proper blog or anything like that. I am just seeing if anyone has the ability or a plugin that can easily be used that will allow me to keep the site as it is but have the function for readers to add a comment as if it was a normal blog. I should also have the function of moderating these comments as well.

Please tell me a total number of hours and cost for completing the full project and how you will do it (e.g. using a plugin etc).

Thanks.