In a bid to build upon my fairly new web hosting company I am wanting to offer people the chance to have 2 months free web hosting for each paying client they bring in.

This means I need a way of tracking which person has brought in which client.

The easiest way of doing this would be to have a script create a URL with the users name in at the end and then when a client orders it sends the username of the person who referred them in a hidden field.

I do not use a script such as whmap or modernbill, instead I just have a bog standard form, on submit it sends the details to me and then sends them to a page with 3 paypal options:

1. Pay for the package monthly
2. Pay for the package quarterly
3. Pay for the package yearly

These are all paypal buy now buttons.

Obviously there are all the places such as hotscripts.com to find a script which i need but there are hundreds to choose from so i need to know if anybody has had experience with one which i could use with a normal form?