score:7
The cheapest option is simple - PATH at $2.75 for the entire trip.
Alternatives are NJ Transit train at $5.25, NJ Transit bus at $6.00, Greyhound starting at about $10, and Amtrak which will be even more. Of course there's also Taxi, RideShare, etc - all of which will be far more.
Despite being slightly more, the best option is almost certainly to catch a NJ Transit train - they are significantly faster than the other options, do not require a change (as PATH does), and has standard train-style seats.
You excluded walking/bike as options, but even these are more expensive than PATH as you need to cross the Hudson which (unless you choose to take PATH!) requires a ferry trip that will cost more than the PATH fare (or a 25 mile diversion to the George Washington Bridge)