When you say "cliffs" to roundabout, you are talking about a wide ranging area. "Cliffs" where? I you are only a short way out then maybe about $5 US for a charter taxi might be appropriate but further out $10 might be appropriate. So it does depend on the location on the "cliffs".
Route Taxis do have fixed rates. Here is a link for what I believe to be an older fare listing but when prices go up in Jamaica, they rarely go up more than $25 Jamaican dollars or so. http://www.ta.org.jm/documents/Fares...stmoreland.pdf As a rule of thumb, you can take a Route Taxi almost anywhere in Jamaica from point A to B for $250 Jamaican or less.
Ask the fare and negotiate a price before you get in. Doing it when you arrive is sometimes a problem depending on the driver.
Peace and Guidance