Do you know the musical habits of the current owner? If they play loud stuff all the time the cones will have degraded. If they play pleasant granny tunes all the time at moderate volume they should be nearly good as new.
Also there is the consideration of cosmetics. Are the cases damages at all?
$200 is not a lot for speakers new, so they are probably not studio monitor quality in the first place.
Will you be able to try them out before you buy them?
Without additional info I’d ballpark about where @zenvelo does, $50 to $75…