Kmart Booragoon (WA) are clearancing Rock Band Drum Sets for Xbox 360 and PS2/3 for only $20.
This is drum kit only, no game, but on checking around, Guitar Hero - World Tour and newer for 360 is compatible (obviously with the 360 version).
Not sure on PS2/3 sets.
Had about 4ish 360 sets, and probably 2-3 PS2/3 sets earlier today.
Could not take a picture, sorry, but bought one myself (360).
You have to keep an eye out for K-mart Rock Band Items, my parents picked up the whole Rock Band set for $20 a couple of months back.. They had them in Wii, X-box and PS2/3!