Referral Tracker URL Param

I need someone to make some Javascript scippet of code to place on my Website (wordpress) that will allow me to track where my customers came from (referral source). Example: [login to view URL] is my website. My 4 primary marketing avenues are: a) Google Adwords and b) Google Places c) Facebook d) Email So, I want to be able to place a "?[referral source] after the URL so as a customer goes to multiple pages on my website, this SOURCE will stay in the browser at all times. Like this: [login to view URL] So, this Source needs to stay with the customer all the way to the CHECKOUT page: [login to view URL] Note: I use a Form Builder called [login to view URL] on my website to gather the Bookings and Billing info so I am not sure if this will affect this Javascript or not? Once the customer is done signing up, I have the form redirect them to the Checkout page automatically. So, hopefully this Javascript code will make sure the "Referral Source" shows up when they land on my Checkout page after Form Submission. Note: I use [login to view URL] to view this and can give you my login to view this if you want. Also, I am open to new ideas on how to do this if you think there is an easier way to do it. I do not want to use Google Analytics as my only marketing analytics because it is too complex and I do not need that much info. All I really need to know is 1) Did they land on my 'Checkout' page and if so 2) What was their 'Referral Source'? THAT IS IT!