Apple is offering a $5 App Store/iTunes gift card when you use Apple Pay to buy items as select retailers now through Dec. 21. You can find a complete list of participating companies by clicking here.
Apple Pay is currently available in 20 countries: Australia, Canada, China, France, Hong Kong, Italy, Japan, New Zealand, Russia, Singapore, Spain, Switzerland, the UK, the U.S., Denmark, Finland, Sweden and the United Arab Emirates.