There is no specific answer for your question. As in anything, there is cheap, average and high quality labor and materials (you buy a Chevrolet or a Cadillac; one is twice the price of the other).
The answers you've received below are right. But first, do your homework by sketching your idea(s) and shop your materials for quality (wood, drywall, windows, bathroom fixtures, tiles or carpet, light fixtures electrical, etc). Then, as per Paul Saperstein's and the Levis' answers, contact several contractors to get estimates based on your pre-developed ideas.
The Levis are correct by saying that the price of construction has considerably come down. That is due to the fact that contractors are nearly starving these days because of the present local and national economy. And, yes, make sure you select contractors that are licensed (check their licenses with the Florida Department and Business and Professional Regulations (DBPR) - (go to www.myflorida.com - click Licensee Search Building and Construction), make sure they are well insured, that they will pull all necessary City of Fort Lauderdale building permits and check for references (not the reference letters they put on their websites -- no-one ever puts nasty letters there -- but call the City of Ft Lauderdale Building Department and ask them about a specific contractor).