How do I create a coupon for 50% off shipping for a specific product?
You cannot set up a coupon for 50% off shipping for a specific product. However, you can discount shipping by 50% on a specific product using the Override Shipping field.
Go to Products/click the Edit Pencil for the product in question/ scroll to page 2. Find "Override Shipping Rates" and check that box. Below that, another section called "Shipping Rates" pops up. There you can add your own shipping charges based on the carrier. Be sure to click Finish at the bottom.