Extremely expensive to hire cars locally.I think even 5 years ago my Brother-in-law paid around 400 Euros, for 5 days hire from a company in Tortosa!!!  If you can jag Car hire from say Reus airport (nearest),then book-on-line.I seem to remember however,that this type of hire may only be available (Officially )to folks who are flying into an airport? I am sure Other TF members will be able to clarify this point. Goodluck