Depending on the exact location in Florida, the cost for a treatment can range from about $150 to about $200. In 2003, according to one study, the average cost per dialysis treatment was $152.95. Most of the information I was able to verify online pointed to slightly higher costs in Florida (although, this could very well be due to increased costs during the past several years).
Here is a link to a complete list of all the dialysis centers in Florida. You can search by city or name. This site also provides all the phone numbers for each center - so you can call them directly and confirm the price.
DaVita, which is the largest provider of treatment in the United States, has several resourced you can use to find a dialysis center in the city to which you are traveling. You can click on this link and enter the city information:
http://www.davita.com/mapquest2/fac_search.shtml
additionally, this is a phone number to speak with a memeber of guest services (they will be able to give you the exact rate): 1-800-244-0680.
I hope this helps you.