Long term parking near nyc

Dear All,
I'm visiting new york city for the summer, and need a place to
store/park my car for three months. I don't care how far away from nyc
the parking/storage place is, as long as nyc is accessible by public
transportation. I would like the parking garage to be in a safe place
where I won't have to worry that my car has been broken into. However,
I am very price sensivite. Ideally, I'd like to find a place in the
$50/month range.

I plan to take a couple weekend trips, but other than that, not use my
car at all.

Anyone have any ideas?

Thanks,
Dave