Approximate Pre-Holocaust Price:
Now that Parkinson's Disease has all but ruined his career you should be able to get him under contract for next to nothing.
Approximate Post-Holocaust Availability:
Depending on the estimated time of ZH0H, Michael J. Fox may no longer exist when you reach in the cupboard for him. Assuming he isn't dead, it may be difficult to track him down if you haven't already arranged post-holocaust delivery with his agent.
Benefits:
Michael J. Fox has captivated the world for years with his dynamic and charming screen presence. When the zombie holocaust occurs who wouldn't want such a talented, well rounded actor on his/her team? Assuming he is alive and isn't a quivering pile of man goo, his advanced Parkinson's shuffle could allow him to operate from within the zombie horde itself. It's hard to put a value on what a nearly wheelchair ridden Michael J. brings to the zombie defense "table."
Drawbacks:
Unfortunately, it's very possible that Michael J. Fox will either cause the zombie holocaust (as a result of his top-secret stem-cell research) or be at it's foul helm (please refer to our zombie threat map). With that said, by the time the zombie holocaust occurs, Michael probably won't be able to say "Huey Lewis and the News" much less stuff his shaky-ass hand in his pocket or help you kill zombies.
Overall Effectiveness Score:
Based on our zombie threat extrapolation algorithms and episode 40 of Family Ties the overall effectiveness of Michael J. Fox falls somewhere between -30 and 11 out of a possible 10.