I would like to know the average length of time homeowners own their
house in Toms River, NJ.

This is just a free comment and not an "answer" to your question that
would charge you the price.

http://www.city-data.com/city/Toms-River-New-Jersey.html
http://www.oceancountyclerk.com/

I am curious about what the average would mean and what you could want
to use it for, but that is none of my business.
Perhaps the county clerk's office, which keeps real estate records,
could give you the number of residential properties in Toms River and
the number of new owners registered for each of the last few years,
thereby allowing a calculation of what percentage of residences change
hand each year and thus a calculation of the average number of years a
residence is owned by one owner.
For example:  if 10% of the residences are sold each year, this would
show that on average a residence is held for ten years.

This would be one sort of average, and seems to be what you are asking.