Consider the Xiaomi Hongmi, also known as the Red Rice. Using the quad-core MT-6589 processor from MediaTek, the whole phone costs Xiaomi $85 for materials. The handset is sold in China for the equivalent of $130 USD. The chip accounts for 20% of what Xiaomi pays for the parts used to make the popular model.
According to those in the know, this low to mid-range priced Nexus model would not replace a flagship spec'd Nexus 6. Still, this project might have become more important for Google in light of the recent leaks involving the long rumored Amazon smartphone. The speculation now is that the Amazon handset will offer a 3D interface with four front-facing sensors. The phone is expected to be unveiled in June, and launched at the end of September with a forked Android OS, similar to what Amazon uses with its Kindle Fire line.
source: MTKSJ (translated) via gforgames