How do I track ad campaigns for an affiliate site? split testing related

I have an affiliate review site and I buy traffic from google adwords primarily. I want to test new campaigns to see if they are profitable, and this is what I'm thinking. I'm new to this, so I wanted feedback on whether or not it's possible and how to do the specifics.

I can attach tracking ID's to my clickbank links, so if I could send my traffic for a certain campaign or ad group to a version of my webpage which ONLY shows links with a certain tracking ID, I would know how many sales I got from those visitors.

So I would need several versions of my website and once someone is exposed to a version with a specific tracking ID, that visitor would then have to see that version of the website every time, so they don't return later (by bookmark for example) and get another ID. Therefore, I'm thinking that cookies must be used.

Is there any software or other solution that would do this for me? Create different versions of the site where I can put different tracking ID's and then "remember" which version of the site to display to each visitor so they always see the tracking ID that was meant for them?

Btw, I guess I could place tracking code on the sales page of my merchants' websites, but I doubt they'll agree to it.

Thanks.