Tracking Users Arriving at One Form From Multiple Sources

Hey guys,
So here is my situation.

I have three forms on our landing page. I also have three pricing options - all of which point to the same form that is in a modal. I’d like to track which form someone filled out (i.e. was someone interested in our $15 package or our $35 package for instance). I used animations to create a pop-up for the form itself.

What would be the easiest way for me to be able to track which form someone filled out? I tried to create 3 different modals with three different forms as this seemed to be the easiest way but the animations got really screwed up and I could never get that to work. Plus, that makes editing the underlying site a little time consuming because you have to hide three different modals and then bring them back up before publishing.

Our site can be seen at nysocialclub.com.

Any help you guys can give me would be much appreciated!

Alfredo