I live down in Port Charlotte. I've used J&J one stop gun shop in PC and Higher power outfitters in Punta Gorda and like them both. J&J has a nice indoor range and a really good on-staff gunsmith. Higher power is convenient to the Cecil Webb outdoor range that I frequent. For FFL transfers, I use county line pawn in Northport. He ships out pistols for less than $20 and charges $15 for incoming transfers.
None of them really have much for used inventory and they overcharge(as do all dealers, IMO). I'd rather deal direct locally with someone who is selling a gun on Florida gun trader or Armslist and eliminate the middleman. Everybody thinks their gun is worth more than I want to pay for it, but with some haggling, I've found some good deals.
The gun shows are always fun, but I usually find a good deal in 1 out of 4 or 5 shows I attend, so you have to figure in the per show cost and tack it on. The best show up in your area is the one at the Manatee civic center in Bradenton. Tampa fairgrounds and Lakeland civic center are also great shows. The one at Robarts arena is smaller, but ok.