If iPhone wasn't made in China by Foxconn?

How much more expensive would this device be if made in USA? Is the cost in labor savings by building these in China passed on to the consumer or simply taken as profit by Apple?

Apple takes the profit. According to Wikipedia -

"The components and labor required to construct the most basic iPhone 5 is estimated to cost US$207… The profit margin of selling each device is 'huge' as the iPhone 5 generally retails for US$649."

The margin is possible because Apple reportedly employs over 500, 000 cheap Chinese factory workers to manufacture their devices. Chinese mobile phone factory workers earn about US$1.00 an hour, compared to American factory workers, who can earn anywhere from US$20.00-$30.00 an hour. With these figures you soon realise Apple could not possibly maintain its current profit margin if its devices were built solely by US workers.

I can't predict how much the device would cost if it was produced in the US, but it would be far too expensive to compete in price with other high-end smartphones such as the Samsung Galaxy S III (which is coincidentally also produced by Foxconn in China). Market share would be lost, and Apple would fail.