Looking for a reasonably-priced way to track my Phantom 2 Vision quadcopter if it decides to fly off, I recently ordered a “GSM/GPS/GPRS Tracker Device” from Amazon.com. It’s a small box that you plug a SIM card into. You call the number associated with the SIM and the device texts its location back to you. Some cell phone operators, such as AT&T, offer “per minute/per message” plans that should work great with it. Most GPS locators require you to pay a monthly subscription fee.
I’m planning to attach the tracker to the Phantom quadcopter. If it gets lost, the tracker should help me find it. The tracker is small enough that I could also use it in some of my rockets to help recover one that happens to drift away from the launch site.