Abstract: A portable communication unit that operates based upon predetermined discrete blocks of airtime. The unit may be operated as a conventional portable communication unit when airtime is available, and operation of the unit for conventional communication is disabled when all the airtime has been used. By entering a specific code, which may be supplied by a dealer, the user may activate an additional block of airtime. Two classes of airtime may be provided; home time airtime which is used when the unit is within the area of a local or primary communication service provider, and roam time airtime which is used when the unit is outside of the area of a local or primary communication service provider. The unit may be programmed, preferably only by the dealer, with toll restrictor codes that limit the available range of numbers with which the unit may initiate a communication session.