CameraLand has a salesman's sample of the Minox 8X25 miniscope listed in a previous post for $89; the regular price is $179.
I purchased one from CameraLand a few weeks ago and am quite satisfied with it. The image is very sharp and bright and compares favorably to that of my Zeiss Victory 8X20, but it is a little harder to hold steady. One of the features I really like is that it has a close focus of about 1 foot (measured by me) and is very handy for looking at plants, bugs, rocks, photos, paintings, etc. It also has an adaptor that allows it to be attached to the top of a walking/shooting stick or monopod; I might find it of some use.
It is smaller than my folded Zeiss compacts, but not by much. However it was 1/6 the cost. The Zen Ray monocular sounds very interesting, but was a little larger than the pocket I wanted it to fit in and doesn't have quite the close focus capability of the Minox miniscope (or is it macroscope?). It might be worth checking out to see if it meets your requirements.
