i bought a Carrefour brand toslink cable last time, around RM10/20 i think... but the head doesn't lock in the toslink ports of both my amp and WDTV. i have to properly wedge something against it to keep it in place. it worked for some time and then after a while it quit giving sound. the tip of the fibre cable seemed very poorly cut, like using nail clippers to cut it.

then i bought a RM120 Philips cable from the garage sale section and it works ok... more sturdy jack head and solid thick cable.