For the 8 GB Nexus 7, the bill of materials totals $151.75, or $159.25 with manufacturing costs included, iSuppli said. The bill of materials for the 16 GB model is $159.25, or $166.75 with manufacturing.

Factor in additional costs such as distribution, marketing and tech support, and iSuppli estimates that Google "will at least break even" on the 8 GB Nexus 7, priced at $199, and will turn a "modest profit" on the $249 version with 16 GB of storage.

Estimates aside, Google Senior Vice President of Mobile Andy Rubin has already said that the Nexus 7 won't rake in the profits. "When it gets sold through the Play store, there's no margin," Rubin last month. "It just basically gets (sold) through."

But there's a bit more room for profit in the 16 GB model, which is priced $50 higher the base model even though the storage only costs $8 more. That would explain why retailers such as and are only selling the 16 GB version. At the moment, the is the only place to get the 8 GB version.

The bill of materials estimate from iSuppli is another example how cutthroat the low-end of the tablet market can be. When the Kindle Fire launched last year, iSuppli estimated a total cost of $209.63, which meant Amazon was losing about $10 on every tablet sold.