I hope you know what you are getting into. I have no personal experience, but all the reviews I read says to avoid like the plague. Here are some of the things I read about.
- Only a few miles a day allowed before they charge you by the mile.
- Ticket counter often closed
- rents substandard vehicles
- Tries to claim you created the damage that was there before you rented
- Generally a cheat
Just search for Firefly car rental reviews. Most would give zero stars if they could.