An old Android phone with the Insane Rocketry app is the best and cheapest tracking system available, if you are launching from a site that has cellular service. With a Nexus 4 or Droid Mini (available on eBay for less than $50), or any other phone with a barometer, with the IR app you also have an altimeter as well as a GPS tracker, and downloadable flight data. The app also remotely controls the phone's video recorder.