There are some great deals to be had if you know where to look.
People say cars are expensive in Spain but is that not now true for every country.
If you know where to go there are some great deals to be had.
Going where the Spanish go.

Years ago i bought a brand new seat ibiza 1300 and as i had just signed the contract in the main dealers i pointed to a car in the showroom and said “ours will be just like that no?
“Yes” he said “the same”. Why do we have to wait 2 weeks then… “That one not for sale” i said.
he explained it was an ex demo car. It was 3400 ish euros cheaper but had around 4k on the clock. it came with all the save guarantees as a new one. so we cancelled our contract and had that one the next day. It was as new even the new smell.
Years later i found a small local garage that bought ex demo cars from main dealers and bought a nissan again a great deal and saved thousands.
Some time ago my bank manager here offered me ex rental or renting cars as they call them here. Many banks now do renting of cars over 4 years and you change the car ever 4 years. these cars are sold off at cheaper prices and some are great deals with low milage.
You need to go to main dealers and small local dealers and ask about these cars.
You can also bargain on the price of these as they have more room to lower the prices.
Many of my Spanish friends have also done this and if i am in the market for another car its where i start first.
I have bought several cars in my 20 years here and a few vans and a pick up truck. i always haggle over the price and walk away coming back a few days later and sometimes even 3 times to show i am in the market but need a great deal. it works these people are keen to sell these cars and there is always room to move on price if you push. Private sales here are much harder to get a good deal as private owners had a price fixed in their mind and dont like to move.
Best places are main dealers or small branches in villages not main towns as they have bigger overheads and dont move much on price. Also getting small amount of finance sometimes help get you better deals.
Over 3 years i have found best.
Some places the spanish look
https://www.milanuncios.com/motor/
https://www.coches.com/coches-segunda-mano/
https://www.ooyyo.com/spain/used-cars-for-sale/c=CDA31D7114D3854F111BE56FAA651453/