Source : Webster's Revised Unabridged Dictionary (1913)

Porterage \Por"ter*age\, n.
   1. The work of a porter; the occupation of a carrier or of a
      doorkeeper.

   2. Money charged or paid for the carriage of burdens or
      parcels by a porter.

Source : WordNet®

porterage
     n 1: the charge for carrying burdens by porters
     2: the transportation of burdens by porters