Clives is $50us pp for one way shared airport transportation to Negril.
Rooster, I can't even imagine any driver running their vehicles/business at the price you suggested without getting at least a couple of paying people for the ride to Negril...it's a waste of time/money for the driver.
If you don't want to pay for a private/charter driver there's a few options as a single...JUTA bus, Knutsford bus...