You can also consider selling your Walmart card by listing it on Craigslist, Kijiji and other local classifieds online or maybe in a newsprint.
For the reason store specific gift cards may end the preferred gift for a few. When it comes to them don't come by using a PIN. https://Groups.google.com/g/giftcard-mall-my-gift-info/c/lJb4jNQqwjY