Apparently Ellie is a repeat customer for the Urine Salesman.
Hopefully it’s clear in the above strip, that like a pokemon, he can only say one thing (aside from shear confusion with “uh..” or probable heavy breathing.) With a mere change in tone or pitch it’s his reaction to everything. What better way to advertise?
Speaking of vagrants. when you have a moment, check out Kate Beaton’s awesome webcomic humor at http://www.harkavagrant.com/