A prototype of the Apple eMate 300 personal digital assistant has popped up on eBay with a list price of approximately $8,500. The listing shows a clear case eMate 300 device running the Newton operating system and is apparently in good working order (even including the original eMate stylus). Notably, the device is marked prototype and is essentially identifiable by the fact that it has a clear case, whereas the eMate models that actually made it to public release sported a dark green casing.
The eMate was original introduced in 1997 and was offered for sale at $800. However, it was discontinued less than a year later alongside the rest of the Apple Newton product line in early 1998. As shown in the listing description, it has a 480 x 320 pixel resolution and grayscale display as well as a full size keyboard and stylus. The design is reminiscent, or perhaps predictive, of the later iBook design.
For those who are interested, and perhaps want to compare it with the specifications of current day MacBook Air models, or even the new iPad, take a look at the specs of the device on AppleMuseum. The 25MHz RISC processor and 3MB RAM / 2MB flash memory might have a bit of trouble keeping up with the some of the latest Apple devices.