According to research firm IHS, Microsoft Surface 32GB costs $271 to build it and TouchCover costs just $16 to build. Microsoft Surface’s main components include a Tegra 3 processor chip from Nvidia, and a display and memory chips from Samsung. Samsung appears to be having a healthy profit from Surface by supplying display, the memory chips and the battery, pocketing about $137 (almost half of total Surface cost).
As every other OEM do, Microsoft seems to be profiting more from the TouchCover keyboard accessory. TouchCover includes chips from Atmel and Freescale Semiconductor and since it’s a compelling accessory for users, Microsoft is trying to squeeze more profit margin from it.
You can read more about it from All Things D here.