These days it's becoming more and more common for the car rental companies NOT to include the accident excess in their rates. This means that when you collect your hire car, you'll either have to leave a hefty deposit (generally between 900€ and 1900€) or pay a daily excess waiver of around 15€ - 20€. The actual liability in case of accident sometimes exceeds the excess deposit.
February/March 2015 saw the majority of Spanish car rental companies introduce an insurance excess. Prices which had previously included CDW (collision damage waiver) without excess, no longer included the excess and, as a consequence, the deposit required on collection increased from around 600€ - 800€ to around 900€ - 1900€ (amount depending on vehicle category). The optional extra cover (which, prior to the introduction of the excess, was just a top-up cover for tyres, glass etc.) became a combined excess waiver and top-up cover and also increased in price, from around 9€ - 13€/day extra to around 15€ - 20€/day extra.
Whilst contracting the excess cover direct with the car rental company offers excellent peace of mind, it's clearly not cheap. A much more economical alternative is to contract a third-party car hire cover, either for your particular dates or as an annual policy. We wholeheartedly recommend one of the leading UK providers of car hire insurance, Questor Insurance, whose rates are as low as £3.49/day or £40 for an annual policy (31 days maximum per rental on an annual policy).
Get a quote here: Questor car hire insurance
Note that if you do contract car hire insurance from Questor or from another 3rd party, you will be required to leave the excess deposit with the car rental company. In the event of loss of any of this deposit, you would claim it back from the third-party cover. Questor Insurance have fantastic customer satisfaction ratings so we're sure this will be a painless process!