There are so many wild guesses in this estimate that it might aw well be next year's federal budget. In fact, I doubt that anyone who worked on those numbers has even been in the same room as the Kindle Fire. I'd strongly urge you to take these numbers with about a pound and a half of salt.
With that being said, iSuppli estimated that the Kindle Fire cost $191 in parts alone. Add in their estimate of the manufacturing cost and the total rises to #210.
I would guess that their estimate is probably on the low side, perhaps by as much as $30. But to be honest I do not know. In any case, we already knew that the Kindle Fire was a subsidized tablet.
Once I knew that it had a dual core CPU, IPS screen, and Gingerbread, I could pretty much guess that it was subsidized. Even if Amazon had stripped it down to the cheapest components possible, the software development cost, once factored in, would have been enough to convince me of the subsidy.
Oh yeah, that's one detail that iSuppli can't estimate. It's a people cost, not hardware, so without inside knowledge it's almost impossible to guess. But you can bet that it adds enough to the cost of each tablet that Amazon are probably taking a loss in the short run.
Of course, once they sell their millionth Kindle fire they won't be taking a loss anymore. But I doubt that will happen for at least a couple months.