A programmable timer for timing the usage of electrical or electronic apparatus comprises a count up counter and a count down counter which count during the on condition of the electrical or electronic apparatus and a switch for selecting the counter output to be displayed on an LED or LCD display. A current/power sensor detects the on condition of the electrical or electronic apparatus and transmits a signal to the counters to count. A keypad is used to preset a time into the count down counter and a reset control resets the timer display to zero. When the switch is set to the count down mode, the display shows the time remaining from the preset time and when the time reaches zero, power to the electrical or electronic apparatus is interrupted. The timer has a locking cover that prevents unauthorized access to the timer controls and unauthorized removal of the electrical or electronic apparatus from the timer. A programmable microprocessor is provided for performing cost calculations based on usage of the electrical or electronic apparatus.