America's sunshine state offered easily the best value for those wanting to hire a car for a week, with Bulgaria the next cheapest destination, followed by Malta.
But Post Office Travel Money warned that holidaymakers who fail to take out excess waiver insurance (EWI) when hiring a vehicle face sky-high charges if they have an accident.
It said costs in Florida were kept down as the state did not charge for EWI. The survey showed that looking at a seven-day hire, including extras, an additional driver plus 40 litres of petrol, the cost in Florida was just £164.69, with Bulgaria £242.09 and Malta £255.49.
Of the other 10 destinations surveyed, Cyprus was the costliest - at £362.29.
The survey also showed how much drivers would have to pay in 20 countries in the event of an accident or theft if EWI had not been paid.
While there was no charge in Florida, the next-cheapest charges were in Turkey (£400), Bulgaria (£404) and Austria (£471).
Andrew Brown of Post Office Travel Money said: "Car hire costs can go through the roof when extras are added so it is understandable that many motorists go for the cheapest rate offered when booking online.
"It can also be very difficult to find out the cost of EWI before travel and it is only when collecting the car that what seemed a cheap deal becomes a very expensive one.
"However, the consequence of not paying for the extra insurance could be a much higher bill if you have an accident or if another driver hits your car and leaves without giving his details."