Basically, as I understand it, in order to circumvent the university's monopoly of $0.55 cokes, the CS dept maintains its own machine and sells for $0.35. The machine itself does not accept money, but instead you need to get an account and write a check to one of the coke machine gurus.

The account will automatically tell you when your funds are low (low-water level set by each user), and you can transfer funds to other users, etc.

Martin A. Reames