The coffee is expensive, being sold at ¥3000 ($30.00 USD in the dub), which matches the ATK of "Blue-Eyes White Dragon". Jack Atlas has drank this coffee on occasion at Cafe la Geen, despite trying to save money.
This coffee is likely based on Jamaican Blue Mountain Coffee, which is one of the most expensive coffee brands.
Blue-Eyes Mountain coffee will be a featured item in the Anime Plaza Collaboration Cafe. It comes with a free sandwich and is the aforementioned Jamaican Blue Mountain Coffee. It can be purchased for 3000 yen and is the most expensive item on the menu.