You'll also need a lockring. A good cog such as a Soma can be had for about $20 and a good lockring such as a Dura Ace for about $10. Anything cheaper, and you risk stripping and ruining the threads on your hub.

Another possibility for you to consider is the Windsor Hour, which costs only $280 and is already set up as a fixed gear. The downside is that the hubs are lower quality, although they are the same as used on the standard Kilo TT.

http://www.bikesdirect.com/products/windsor/thehour.htm