The rules that I have established for buying a player are
pretty simple:

a) Does it pump easily?
b) Do all notes play, and with reasonable repetition?

If the answer to (a) is "no" then it suggests that serious work
is needed to bring it to a workable, thus saleable, condition.

If the answer to (b) is "no" then clearly some investigative work
is needed, and suggests that there may well be problems with other
notes at some time in the future.

Upon either test failing I would regard that as a non-working player
and would therefore personally not pay more than 300 dollars for an
upright pedal-action half-Duo-Art.  I would not even pay money for
a standard player that failed both tests.

Roger Waring
The Pianola Workshop
Solihull
England