KUguardgrl13 is correct. You'll save some money by going the separate pieces route. I will warn you that if you go this way, sometimes the adaptor is a little bit finicky if it gets twisted at all. The one my fiancée picked up from Fry's throws a fit if it twists more than like 30º. Works well enough once we've got whatever site we want set though.
Still cheaper than the all in one route though if looking at established brands like Belkin. Check Amazon, i found a cable going for about $8 with free shipping.
Also, a perk of having just the adapter and supplying your cable is that you can find whatever length you need and have more flexibility in that sense.