Are all fees included in the cost presented?
Yes, unless you add extras as SAT NAV or additional driver, which are quoted and can be reserved both during the online booking process BUT they are paid at the desk on arrival.
What is the minimum age to rent and how much is the underage fee ?
First thing to say is that, regardless the age, the driver must have held a full driving licence for at least one year.
To find out what is the minimum age and if any extra charges apply, please click on the link "terms & conditions' displayed to the right of the car photo of your choice. This will open another smaller window and if you click on "driver's age" you will see what age restrictions there may be and any associated fees. Try a few different car models / suppliers, as they do differ.