Thank you so much. I followed the steps and it works almost to my needs. There is still an issue, though:
* I set “Limit usage to X items” to 1, because I only want to use the coupon for 1 item to be discounted 100%, regardless of how many items are added to the cart;
* I then add 5 items to the cart;
* (I believe this is what is happening) the second item added to the cart is discounted 100%.
What I really want to happen: the lowest of these 5 items (or 3, or 9) to have a 100% discount.
What is that I am overlooking?