Jeanette
Cars are not all that expensive, especially with the crisis. As long as you do the transfer through a gestor you will have no problems with back debts etc.
I have a 1997 Toyota Corolla, from new, 70,000 Kms, never had to spend a penny on it, except servicing, everything original. If I were going to sell it I would be lucky to get 1,500 euros. It would cost you more than that to import your car and a lot of hassle.
Buy a car in Spain, or even look at the cost of hiring against owning, buying cost, transfer fees, depreciation, servicing, tax, insurance, parking, vulnerability whilst parked, etc.