Economics à la Bill Watterson's Calvin

Lemonade at "15 bucks a glass?!" Susie explodes, dumbfounded at Calvin's audacity.

"That's right! Want some?"

"How do you justify charging 15 dollars?!" asks Susie.

"Supply and demand," says Calvin.

"Where's the demand?! I don't see any demand!" says Susie.

Oh, replies Calvin. "There's lots of demand!"

"Yeah?" challenges Susie.

"Sure!" says Calvin. And he proves his point.