beach sand will almost always contain contaminants. if you have a friend who has a boat, you can motor out into the ocean a ways and use a bucket and a rope to scoop some sand off of the bottom. check local alwas as there might be places this is illegal. alternately, since you are in florida, live sand from lfs should be relatively cheap.
personally, i would recommend getting some skanky live rock and starting your cycle with that. as the stuff dies off, the ammonia it creates will feed the cycle just fine. the main problem with using live sotck aside from ethical reasons, is that most of the fish that will survive the cycle are absolutely horrible community fish, and will terrorize anything you add down the road unless you get something bigger and meaner than them. that will quickly start to rule out a lot of the more common peaceful fish.
you can run a tank with only hang on back (hob) equiment, including powerfilters, protien skimmers, closed loop circulation systems etc. but you are limited to the few brands that create the equipment, and in many cases when you start to get over 50 gallons, the quality and effectiveness of these things starts to go downhill.
the biggest benefit of the sump (the underneath stuff in a reef ready) is that all of that equipment will not be inside your tank, or behind it (forcing it out from the wall) and that you have a larger selection of equipment to use, AND you get more water volume which adds to stability.
hope that helped instead of making things more confusing.