McDonald's is giving away free fries! All customers have to do is use their Apple Pay with the McDonald's mobile app take advantage of the promotion. The first day of the promotion is Friday, July 12. In recognition of National French Fry Day, which is July 11th, when you spend at least $1 using Apple Pay on the McDonald's app you'll be eligible to receive a free, medium-sized french fries. The promotion will continue on Friday, July 19 and Friday, July 26.