Using online sites like
To get an estimate at the Portuguese end.
Hiring a car seems to cost between 300 to 400 euros per week in Portugal at end of May for a Compact car.
Buying excess cover seems incredibly excessive.
Renting a satnav from the car hire firm seems outrageously high @ 12 euros a day.
And all the other add-ons.
Add on the price of petrol and motorway toll fees, and perhaps rental of one of those auto toll paying devices for some of the highways in Portugal, it all seems sky-high.
None of these web sites says whether you can use the car to go into Spain or not. Or whether it costs even more to do that.
I thought Portugal was in recession. And car-hire were wanting to give away their cars during the off-season.