Creating a dating site

Hi

I have an existing established website, which I don’t want to alter at all except for to add the extra feature of a dating section. The website itself is not a dating site, this would simply be a feature of the site as it stands totally unrelated (may sound daft but I do have my reasons!)

The thing is, I can’t seem to find any good solutions to get this part of the site up and running. There only seems to be one plugin, and that’s $200, which I just don’t have right now. I need something cheap or even open source if possible!

Something I noticed is there are more themes available than plugins, but how would adding a theme affect my existing site? Would that mean I’d have to install multisite? I’m not sure I want to go that complicated. Is there a simpler way?

Have I missed any plugins which can be used for this which are cheaper? I already have a directory and a classifieds plugin running on the site, so can’t add any more of those as they could conflict with each other.

Perhaps purchasing a script is an option? I’ve never done this on wordpress, is that complicated? Reliable?

Any suggestions more than welcome!

Thanks ??