Found my answer from wikitravel page titled "Montego Bay"
To get to Negril, you'll have to take a bus or route taxi to Lucea. The fare to Lucea is around $100JMD. Where the bus drops you off in Lucea, there will likely be a route-taxi waiting to fill up and take you to Negril. Again, the people hanging around in Lucea can generally be trusted to point you in the right direction. Lucea-Negril was around $200JMD.
That sounds like $300 JMD....wow!