I took the ride share service from FLL to my place in South Beach two weeks ago and it was $18 each way. It's called Airport Express and you can find the web site
here.
On your trip TO the airport, you need to make a reservation and they will pick you up within a 30-minute window about 2.5-3 hours before your flight. However, going from FLL to anywhere else does not require a reservation. You simply walk up to their curbside booth and tell them where you are going. When I used this service after arriving at around midnight, nobody else was going to my part of town and they didn't want to use one of their vans for just me. So after about 20 minutes of waiting, they called a cab for me because they were not going to be able to honor their 30-minute wait guarantee. The cab ride was as quick as can be, there was no traffic, and the meter ended up reading $74.50...but I only had to pay $18 because it's Airport Express' policy to pick up the remainder of the tab.
I've done a lot of researching on this subject and from what I've seen, Airport Express is the cheapest shuttle service available unless your hotel/cruise line offers one. Unless you are a mass transit freak, I would not recommend that a tourist use tri-rail if they can avoid it, especially if you are going to be carrying baggage.
