There are currently 20 partners on the page. Worth a look. From the fine print:

Offer valid in the U.S. only, while supplies last. Limit one App Store & iTunes Gift Card per partner.

Makes me wonder how these sorts of partnerships work. Is this $5 straight out of Apple’s pockets, a promotion to help push Apple Pay use? Do the partners kick in some or all of that $5 for the exposure on Apple’s site?