Amazon and Square Enix have teamed up to offer a new promotion that benefits Final Fantasy XIV players, and it involves the life-encompassing mount system. If you spend $19.99 on "any game," you get the Black Fat Chocobo Mount for free: the promo is running through July 1, which is the day before the new Shadowbringers expansion launches.
Basically, if you spend $19.99 on "any video game," you get the mount for free as DLC. There's a proviso involved so be sure before you pull the trigger: it needs to be purchased from Amazon proper, not a first-party seller. Just make sure the logo is on the thing you're buying first (it'll show up as a "product alert"), and the easiest way to satisfying it now is to get a game time code for XIV. It's a fairly big promotion given that it spans all of gaming and focuses around the darkness-tinted Shadowbringers expansion, so you know Square Enix is trying to strike while the iron is hot and the subscription-base is high.
As a note you can still get the regular Fat Chocobo mount in XIV if you're a previous Collector's Edition buyer or you earn 3000 player commendations ("thumbs-up after a group activity").