It's $187.51 to make a 16gb iPhone 4and they sell them for 600 to AT&T. The've sold over 14 million units of the iphone 4 since launch, this means Apple has made at least 4 billion in profit on them.
iPad, I don't know the cost per unit but I imagine it's about $220-230, if not a little less, yet even the refurbished 16GB is $449.
Android tablets... Google is waiting for hardware manufacturers to make them. This is blah. Google could sing 1 billion dollars into designing a tablet, make the money back many times over in 6 months and it would be a superior device. But aha, the cool part is, Google could go to Hon Hai Precision/Foxconn like Apple, and build it with off the shelf components, make an awesome tablet, and probably only spend a million in r&d making it.... and forget advertising, the damn thing would sell itself. They could then sell the device for 250-350 and absolutely own the tablet market... Google, if you are listening get into the hardware busines! PLEASE!