If you're looking at any kind of volume, you should be able to get Chromebooks for under $100 direct from China. When I was at a K12 school about 3 years ago, our purchase of ~250 Chromebooks allowed us to knock nearly 25% off the per unit cost to get them down to ~$150/device. And that was going through a third-party that was white labeling the devices.

The machines we ended up with were 2GB of RAM/16GB storage devices with 11" screens. Basically they were the reference designs Google released a while back when they opened up Chromebook manufacturing. And for the 4th-12th graders we gave them to, they were amazing.