Get

Buy it fully assembled (easiest!)

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/EXPCK1-2.jpg

APM is available fully assembled with a range of options from Udrones.com. The base version with GPS is $299, which is all that is necessary to fly an aircraft. You can also add a magnetometer, airspeed sensor and/or two-way telemetry kit .

Buy a kit (cheapest!)

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/KT-APM-01-2.jpg

If you're comfortable with some simple connector soldering (no harder than the soldering of motor connectors that most RC hobbyists do routinely) you may prefer the APM kit.

It is available for $250 from the DIY Drones store. You can add a magnetometer, airspeed sensor and/or two-way telemetry kit there.

And get something to fly it in!

You'll also need at least a five-channel RC radio setup, a soldering iron, a mini USB cable and of course something that flies!

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/BIXLERMODE2165423.jpg

For beginning RC pilots, we're partial to the HobbyKing Bixler, which comes in an Almost Ready to Fly kit without a radio, so you can add a radio that's more appropriate to a UAV (at least five channels)

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/skyfun.jpg

For expert pilots, we recommend the SkyFun delta wing, which also comes Almost Ready To Fly, with servos and motors installed.