When I heard Microsoft was going to discontinue the Zune I purchased all the extra items I needed (wall plugs, charges, docking stations and cables).  There are numerous vendors selling them and you need to factor in the shipping costs but all in all you should expect to spend $3 - $4.  I have a about 5 cables in place right now as I have several zunes and use them on several computers and docking stations.  So far they work great, the fit with the zune is fine and they come off with ease.  If these are knock offs as some people claim they pass the test.  I have 3 zunes and have no problems using these cables.