I don't see how it could get any cheaper.
http://shoptemp.com/products/Component-Cable-for-Nintendo-Wii-p-72.html for $10. Also, their is http://www.dealextreme.com/details.dx/sku.4256 for $5. And http://www.amazon.com/Component-AV-Cable-Nintendo-Wii-HDTV/dp/B000MTVWAQ which I think is really cheap if they're telling the truth, or I'm not mistaking.