Over the years, I've collected literally dozens of USB -> 30 pin connector cables. I'm sure you've got a bunch lying around, too.
But now that I've got an iPhone 5s, I find myself shopping for extra USB -> Lightning cables for other rooms and places (one each for the car, the bedroom, the living room, the get-a-way bag, etc). I was in the Apple store and was going to pick one up until I saw the price. DAMN APPLE!
Well, according to Wirecutter, there's a reason for that. http://thewirecutter.com/reviews/best-lightning-cable/#