Here is how to build your own feederhttp://flightaware.com/adsb/piaware/build
Flightaware gets aircraft information from these and other devices as well as from other sources.
Some information is from the FAA.
A simple unit can cost as little as $US60 to put together.
One of mine has a small antenna that sits 3ft off the ground on my basement window bars. It can hear aircraft 60 miles away, in some directions. A roof mounted antenna can get 200-300 miles depending on location.
Flight aware makes it easy to setup with their own image on an sd card.