http://www.ebgames.com/ebx/product/238962.asp
It is $20 in EB and such stores, but you might luck out and find one on Ebay. The one in the green box on Ebay is C.R.A.P.(Carelessly Reproduced Annoying Poopy). there is a delay from the time of button press until said button press processes. The one listed above is by Gemini and I use it myself. I am not the DDR god by any stretch, but people better than i use it also and say it is worth the money.
_________________
If you are not you, who are you?