As for the not shutting off with the key, is it a K series or a Magnum? I'm going to guess a Mag. with that issue could be as simple as a bad ign. switch, or a broken wire, if it's a Mag. K series don't normally have that problem.
Not all tractors have hour meters and yes the fail, in fact tractors I've had here more did not work than did work, start and drive the tractor for a few min. the meter will move if working.
Being a 8 speed I don't know of any critical issues, just check it over for abuse, things not greased, oil black, general cond. was it cared for, ect......
As for price that is hard to say, with out any attachments depending on cond. running driving $300 to $700 if very nice with no issues, attachments add value but only as to how nice they are, if he is asking near $1000 it better be nice, not perfect but nice ready to use.