Florida as stated in my Call to Arms post has various rules in different Counties and Cities. Even though the only laws we must comply with are the ones specifically set out in the State Constitution, the Local Cops take pleasure in making sure we comply with the Local laws.
In most of Florida, the only rule is that you don't sell to anybody you know to be disqaulified. I have sold 3 Guns at a Gun Show in NW Florida with No Problem.
But, I can't even buy a gun in Miami. Miami-Dade, Broward, and Palm Beach ban Private Sales. They do this by requiring a NICS check. But, under FLorida Law I cannot perform a NICS check, so I cannot sell privately. Also, Miami has this cockamamy rule about banning minors under 21 (since when has 18 to 21 been a minor) from buying guns in Miami-Dade. Miami-Dade also has a ban on "Saturday Night Specials", which they define as any gun with a barrel less than 3" in a Caliber of .32 or smaller. How long is the barrel on a Russian Tokarov (.30 Caliber) ?
But, as I said all these laws are in violation of Article 1, Section 8 which was added to the Constitution in 1990 and FRS 790.33 passed into law in 1987.