Antikythera mechanism working model
I agree completely with your value estimate. When I think of just the DESIGN of this mechanism, my head swims. a box of 340cm Length (11.15") by 180cm W (5.90") by 90cm D (2.95") containing a minimum of 30 bronze gears and hand crank - WOW!!
There is a short but very interesting YouTube video of a London, English Museum Curator, Michael Wright, describing his multi-year effort to reconstruct the mechanism (2008). Given that one side displays the visually retrograde movements of the 5 known planets of the time, that apparently were 'handled' by multiple gearing.
The Wikipedia article on this mechanism does indicate (at bottom) that the design was in advance of the available mechanical skill needed for the implementation. Still I would imagine that this entire mechanism required a very wealthy patron, a designer close in skill and knowledge to Archimedes and a master-level workshop and artisans to produce it over a period of years!
Indeed, it may be a push to assume that it really worked or worked reliably! It could have been the equivalent of a White Elephant, known to have great potential but so balky and cranky as to be totally frustrating!
I doubt that. I believe that we have found multiple written references to what we now know were Antikythera devices.
Antikythera mechanism working model
