1. A computer-implemented system for tracking physical objects, comprising: pairs of associated identifiers and trackers; a dispenser to provide one of the identifier-tracker pairs to a user, wherein the user places the tracker with a physical object and to receive from the user the identifier of the provided identifier-tracker pair; an identification module to identify the tracker that corresponds to the received identifier from the identifier-tracker pair provided to the user; a tracker location determination module to determine a location of the tracker, comprising: a monitor module to monitor readers within a defined area; a plurality of readings comprising the tracker obtained from the readers; and a location calculation module to calculate a location of the tracker based on the readings from a plurality of the readers; and an object location determination module to designate the location of the tracker as a location of the physical object on which the tracker is placed.