USB Powered PC Speakers, $14.95 @ Jaycar Electronics
Portable USB-powered speakers for use with laptops, desktop PCs or mobile music players. Contemporary, space saving design with plug and play functionality. Separate volume control, power switch and headphone output, and as they're powered via your computer's USB, there's no need to use a plug pack or batteries.
Impedance: 6 ohms
Power output: 1.8WRMS
Frequency response: 160Hz - 20kHz
Dimensions: 154(H) x 75(W) x 36(D)mm
buy in store, otherwise cheapest shipping option is $6.60 Australia-wide...