I need to buy an usb power adapter, but I don't want to spend over $30 for that small device. I see ebay has them for less than $4 with free shipping. Anyone have used it? How good and safe are they? Are there better ones around $10? Any recommendations? BTW, how much would a 'real' Apple usb power adapter cost Apple? I am guessing less than $2 each from the Chinese supplier. $29 price is just absurd.