In Alabama, which is pretty close to Florida's summer torture, I have a fan which helps a tiny bit, but my shop is a converted barn with 30'+ ceiling, lots of square footage there! My saving grace is I am facing North and have BIG doors on both ends that usually pull a nice breeze through the shop...sometimes! I have no windows, and that doesn't help either! The thing I try to do every year is to acclimate to the temps-before the heat really kicks in, drink lots of H20 primarily at night, and abstain from alcohol,<I don't drink anyway> which will dehydrate you in a minute. Florida is brutal with the temps and humidity, as ole Bill C. once said, " I feel your Pain".
The best most economical idea I can think of is to create a cross draft, by putting a strong fan on a window on one side and then having another window/opening on the other to pull the air through the shop, it maybe HOT air, but with a good coating of sweat, it feels WONDERFUL!. Good luck, and be COOL! Rex