Looks like an open sourced OS alone may not make Google Chrome OS based netbooks cheap and affordable like the MS Windows counterparts. Folks at Netbook Choice write that the netbook being envisioned by the Big G is expected to come with a lot of high end features including high resolution displays, 64GB SSD, integrated 3G modem etc. that purchasing a Windows netbook may work out to be cheaper.
While paying for a higher end device is a no-brainer, it needs to be noted that the platform does not support many ubiquitous software including Microsoft Office which means that you may be buying a higher end device that can actually do lesser.
However, support for software as this is expected to roll out as Chrome OS proliferates which will nevertheless take some time.
[Netbook Choice via Lilitputing]