Setting up one coupon/discount for multiple items to show free in cart

[LSowell]

I recently hosted a giveaway for some items on my Square site. I'd really like to be able to create a coupon/discount to be used that will allow the giveaway winners to go into the site, choose what they want, apply the coupon and checkout for free.

For example, one winner won 4 standard size greeting cards. I have 4 greeting card item listings with multiple standard size options listed. They should be able to choose any 4 standard cards from any of the item listings, add to cart, add coupon, and the cart should show $0.

I tried doing a coupon 2 ways -- the first being "free" and choosing the items that apply to the giveaway and "can use coupon" and set it to 4. When that didn't work, I tried "free", chose the items, then set to can redeem up to 4 times. That also didn't work.

So then I tried doing a discount using the exact item/quantity option. I set it to 4 and again picked the cards that applied to the discount. That also didn't work.

I'm really struggling to believe there isn't any way to set this up to work and feel like it's most likely user error.