Last week I wrote about confusing coffee pricing: Wawa, a Philadelphia-area convenience store chain, charges $1.25 for 32 ounces of coffee and $2.99 for 64 ounces. $2.99 is more than twice $1.25. Various commenters pointed out other counterintuitive pricing (train or airline fares that don't obey the triangle inequality, for example). Paul Soldera pointed out in a comment that the reason for this may just be that there aren't that many mathematicians out there, and $3 for 64 ounces of coffee sounds like a bargain to most people.
Paul Soldera may be right -- but I discovered another candidate explanation for this pricing today. Namely, I took a closer look at a sign (at a different Wawa from the one I normally go to), and it said that the 64-ounce "includes supplies". In other words, they're not selling this as a giant cup of coffee for one person to drink, but as something from which you can pour multiple cups for multiple people. Thus, they provide the cups, and perhaps other coffee paraphernalia as well.