A used Garmin Astro can be purchased from Amazon.com, Double U Hunting Supply and Outdoor Dog Supply. As of 2015, prices vary from $120 to $299.
The Garmin Astro is a handheld, GPS dog-tracking device designed to enable hunters to spend more time looking for game instead of searching for a runaway dog.
The device works with a wireless transmitter called a DC 20 to obtain a satellite signal and pinpoint the dog's location. The screen provides a compass that leads an owner to the dog and even tells the dog's position, whether sitting, running or on point. The Garmin Astro sounds an alarm when a dog goes on point or sees something interesting to him, possibly prey.
The device can track up to 10 dogs at a time up to 5 miles away. It can also keep track of useful information about prey, such as the location, time of day and count.