Shit won't work. As "you" is referring the player controlling the artifact. For instance, if the controlled player would have a spell that says "You gain 3 life", the controlled player would gain that life, not you, as the one controlling him. You could make him force you to get him an expensive drink and pay for it himself. But what do you have from this instead of being a complete douche?
To clear it up:
Tap, Sacrifice
Ashnod's Coupon: Target player gets
you target drink.
Errata:
You pay any costs for the drink.
There are two instances of "
you", both must referr to the same player (the one controlling the coupon).
Sorry for you, that it won't work, as I like your idea, but life isn't always a bowl of cherries.