I've seen many comments on Eurocar, Carjet, and Autoeurope. Has anyone used www.doyouspain.com
Their rates are lower by far and include Fully Comprehensive Insurance coverage. They are quoting only 63 Euro (~$86) for a 4 day rental!
OK, that price seems like a bad misquote - I am now seeing 173 Euro - similar or higher than some o the others. Maybe I mis-entered something. Still cheaper by a good chuck than autoeurope.
I used autoeurpoe in France and was well pleased...one note, they did put a hold on the card until well after I had returned home...luckilly I did have another card! :-)