We just bought a new car in June. I found
carnovo.com useful, it's a great idea where official dealers blindly bid to sell you a car. We didn't buy via the site but specified the car and options we wanted, waited for the offers to come in then contacted a local dealer to see what he would match. Knowing what other dealers were prepared to do was definitely helpful in negotiating.
Regarding finance, I'm suspicious of any loan but it seems that the interest is basically the amount they discount from the cash price, so if the car is listed as 15k with finance at the end of four years you will have paid around 17k. However if you try to pay cash they'll bump the price up to 17k anyway!
So with the associated 5 year warranty, four year maintenance, one year free insurance and the rest of it (I think we have tyre insurance for >1 years too), financing just made sense.
Finance advice: They will try to add on insurance for the finance, things like loss of employment and loss of driving licence. If the dealer won't cancel these for you (apparently some refuse) just contact the finance people direct and they will. Also, if you opt to pay the commission for opening your loan upfront in cash, you'll save the amount of interest you would pay if these are rolled into the loan (as they are by default). More details in Spanish here:
https://www.clubseatateca.com/threads/e ... cuota.239/ I only read that site after signing the finance but had enough time to e-mail and get the insurances cancelled; it saved around 500€ which was deducted from the loan, so good but definitely better if you can refuse before it's set up.
So in the end we bought new here - having never done so in the UK. The difference between new and used prices just didn't seem big enough to justify losing years of warranty and be out of step with the emissions schemes. Depends what you're buying I guess, but for the sort of small car we wanted it was clear. Even got a 700€ 'trade-in' for just showing them the paperwork of my old car which I then sold on for scrap, so combined, more than I would have got selling it privately.