Your better of buying a new PS2, get one used from Amazon.com for $70 or try one of your local game shops to try and scrape a better deal.
But this website is genuine and has one for £10 which is about $20. Plus shipping and tax your looking at about $35.
http://www.consolesandgadgets.com/catalog/dvdcd-ribbon-cable-v4v10-p-1706.html