I don't know of any place in Ft. Lauderdale that sells the kind of line most of the racers use. I get all my stuff from Annapolis Performance Sailing (http://www.apsltd.com
For sheets, New England Ropes Salsa is preferred by a lot of people. 5/16" (8 mm) is about $1.21 / ft. (mainsheet) New England Bzzzz line is another good choice. Jib sheet is 1/4" (6.5 or 7 mm)
Aussie jib halyard is usually a single-braid Spectra line - Samson Amsteel or similar. 3/6" (4 mm).
My righting lines tend to be sections of old mainsheets. I've got some old Maffioli Swiftcord and Yale Light as righting lines.