The Beldon 1694A from Blue Jean Cable. BNC/BNC terminations at 6 feet for $21.50 plus about $8 shipping. This cable is actually quite good and I found that I liked it better than some other more expensive cables (in the $50-150 range).
You can have it terminated with other combinations as well if you wanted, such as RCA/BNC.
You can have it terminated with other combinations as well if you wanted, such as RCA/BNC.