I should have told you that the few times we paid to park we were taking 5-night cruises (Bermuda/Canada). Plus, our cost was being split 4 ways so it only came to around $20/pp.
When we do the 9-night cruise we have a van/limo service take us to and from the pier. We live in Pennsylvania, which is two hours from Bayonne, so its nice having someone else do the driving.
Bottom line is that you have to find out what would be best for your situation.