Countdown timer on discount products pages
You can use the Field Timer module


  This module provides field which can be displayed as a
  timer/countdown. A start/target date can be any date or an entity
  property which represent a date (for example, created date of a node).
  Module provides 4 field formatters: simple text and 3 formatters based
  on jQuery plugins County and jQuery Countdown. If you are looking for
  a configurable countdown/timer, this module is for you. It allows to
  configure backgrounds, effects, formats, language of timer.


OR

Countdown Timer Field


  Countdown timer field module allows you to create countdown timer
  field to count the days, hours, minutes, and seconds until a specified
  event. The module uses jQuery Countdown Timer to display the countdown
  timer in a nice graphical way.