I would say thats a little on the high side. There's one here in Florida here in nice condition for $600 with the chrome drawer pulls. The ones I see around here in that condition seem to run in the $400-$500 range which seems fair.
Agree with above. I feel $700 is too high. I would pay up to $350-$400. Depending on what it looks like / works in person. In my experience alot of folks say that their tool box is in "good shape" and "works great" when really the drawers stick and rust is abundant.