What I am trying to figure out is if their is the functionality or a contribution that adds the functionality to give the customer the choice to add a special product to the shopping cart. When a customer goes to checkout, I would like to offer the customer a special product that they can add to their shopping cart at a discount price before proceeding to checkout.

If anyone knows if this can be done via the standard functionality or a contribution, please let me know.

If needed, here is some system info:

osCommerce 2.2-MS2
PHP Version 4.3.10