Are you sure it was ignition timing that was the problem? Could it be valve timing. That would make more sense as to why someone would give up on a car and sell it for $200.
If this is the case you would need a new timing belt. I don't know if there is a valve clearance issue with those engines though. If there is, the valves get bent when the timing belt slips. Someone with a zetec will have to chime in to answer that.
