I would like to add a global gift wrap option to our checkout pane on Ubercart 3 (running on Drupal 7).
It is an option that can apply to any product and has a fixed price no matter how many products are purchased.
I do not want to add it as an attribute to individual products or product classes, but would like to add a simple yes/no radio button to all checkouts. If yes is selected, the fixed amount is added to the order.
What is the simplest/best way to implement this?