If you love McDonald's fries, here's a salty-sweet deal you won't want to miss out on.McDonald's announced it will be giving out free french fries for the rest of the year.Every Friday until December 30, you can get an order of medium fries for free.But, there's a catch!In order to get your free fries, you must download the McDonald's app to get the coupon, and you have to make a purchase of at least one dollar.And after all, who doesn't love free food?