Dogma: The air mouse sucks, don't get it. Not worth it, seriously.
Tibs: Go on Newegg and try to build a computer for $500
Here's my best shot at it: I got you out of there for less than 500.
The setup includes:
Dual Core AMD processor
Motherboard (compatible ofc)
2gb DDR3 RAM
Nvidia Card with 1gb RAM
19inch Monitor
500gb SATA HardDrive
SATA Cables
Keyboard
Razer Death Adder Mouse
Speakers
Computer Case w/ 480w PowerSupply & Fan.
Here's a screenshot.