Mathematic Drinking Dynamics

Frank: Holy shit, this is the first time I see a proper application of a mathematic concept in real life. Take this party for example. The entry is $15 and it's all you can drink. So your first beer costs $15 but each subsequent beer you drink brings the cost down until you reach an asymptote where it becomes virtually zero but not quite.
Nick (engineering student): I'm surprised you're in English Lit and you understand what an asymptote is.
-On saving by drinking