This is such a really cool set of quadcopters! It's a shame it's got a couple of pretty decent-sized flaws, but if you keep it close to you, it's an amazing amount of fun!
2-Quad Set: http://shrsl.com/?~9o2q ($41.25!)
1-Quad + Tower Set: http://shrsl.com/?~9o4g ($28.46!)
Frequent Flyer's Video: https://www.youtube.com/watch?v=-CsNHXtkAj4