According to the Consumerist blog:

On Saturday, "Andrew" allegedly ordered a massive, 60-espresso-shot 128-ounce milkshake, which would have cost an astounding $54.75. 

Luckily for Andrew, he’s a “Gold” member of Starbucks’ loyalty program, which snags him one free drink for every dozen he buys. Unfortunately for Starbucks, the chain didn’t stipulate how large or expensive the drink can be.  (Yahoo)

Click here to find out what the drink was comprised of.