wrote:
I am debating between taking a flight into Miami or Fort Lauderdale.
The ticket to FLL is $120 cheaper. If I take a taxi I'd lose my
savings on the extra fare. What is the cheapest way to get from the
FLL airport to South Beach?

The cheapest would be the TriRail shuttle from the airport to the
Tri-Rail station, then Broward County Transit Route 4 from the Fort
Lauderdale Airport Tri-Rail station to North Miami Beach (or Golden
Beach) and switch to Miami-Dade bus K to South Beach. I'm sure that this
would take at least two and a half hours. On the plus side, most of the
route is down A1A, so at least it's interesting (if you've not seen it
all before).

http://www.broward.org/bct/pdfs/rt4.pdf
http://www.co.miami-dade.fl.us/trans...routes/111.pdf

Also see "http://www.floridalimo.com/Pages/sharedr.html" I've never used
them, but it seems similar to Super Shuttle, and it's $18 not including tip.

Are there any public shuttles that go back and fourth taking whoever is there? What other options do I have and
worst case, how much more would it cost to take a taxi from FLL
instead of Miami?

If you arrive early in the morning on Friday, Saturday, or Sunday, you
can take the water taxi from downtown Fort Lauderdale to South Beach for
$22. See
"http://watertaxi.com/Event/DisplayDetail.Asp?ID=250&EventID=250&TemplateID=1& ContentEntityID=128"

how much more would it cost to take a taxi from FLL
instead of Miami?

A lot. It's very far. $75 minimum.