What makes a used car cheap to run?

Running costs are the part of buying a used car that people work out last and regret first. The price is one number. What the car asks of you afterwards is several, and most of them you can find out before you hand anything over. Here is how each part works, and what in a car's own paperwork tells you which sort it is.

What actually makes a used car cheap to run?

Four things do most of the work: how much fuel it burns, which vehicle tax band it falls in, what it costs you to insure, and what condition it is in on the day you buy it. The first three you can check in advance. The fourth is the one that catches people out, and it is why a car's service record and MOT history matter more than the number on its odometer.

A small, light car with a small engine will usually drink less fuel than something big and heavy. That part is obvious. The part that is not obvious is that two cars of the same model and year can cost wildly different amounts to keep on the road, depending on what has been done to them and what has been left undone.

How is vehicle tax worked out on a used car?

It depends on when the car was first registered. For a car first registered between 1 March 2001 and 31 March 2017, the vehicle tax is set by the car's CO2 emissions band — the lower its emissions, the lower the band. For a car first registered from 1 April 2017 onwards, there is a standard yearly rate instead, plus an extra charge for five years if the car's list price when new was above the threshold.

So a well-chosen older car in a low emissions band can sit in a cheaper band than a newer one. The bands and the current rates are on GOV.UK, and you can look up any car before you commit to it.

Do I have to tax it before I drive it home?

Yes. Vehicle tax does not transfer with a car when it changes hands, so as the new keeper you have to tax it before it goes on a public road — you can do that online straight away using the reference from the V5C. The car also has to be insured before it is driven on a public road, and that includes the drive home.

There is more on both here: Do you need to tax a used car before driving it home?

Does a small engine always mean cheap to run?

Not by itself. A small engine in a heavy car, worked hard, can use more fuel than a larger engine doing an easy job. Short trips, a roof box, town traffic and a heavy right foot all cost more than the engine size on the logbook suggests. Match the car to the driving you actually do, not the driving you think you ought to do.

If most of your miles are short runs around Wrexham, a small petrol car tends to suit. If you are up and down the A483 every week, something with longer legs may work out better even if its tax band is higher.

How do I tell what a car is going to need spending on it?

Read its MOT history, and read it properly. Anyone can check any car's MOT history free on GOV.UK using the registration number: every test, the result, the advisories, the failures, and the mileage recorded at each test. That gives you years of evidence about how a car has been looked after, written by people with no interest in selling it to you.

What to look for:

• Advisories that repeat. The same note year after year means something was flagged and left.
• Mileage that climbs steadily. Big jumps or flat years are worth asking about.
• Failures for corrosion or suspension. These are the expensive sort.
• Gaps between tests. A car that sat unused has its own set of problems.
• A service record that matches the mileage. Stamps or invoices, with dates that line up.

Our guide How to check a used car's MOT history walks through the GOV.UK check step by step, and What to check when you view a used car covers the car in front of you.

When will the car need its next MOT?

In England and Wales a car needs its first MOT by the third anniversary of its registration, and then every year after that. So on any used car old enough to have been tested, there is a test date coming, and it is worth knowing how far away it is before you buy — not because a test is expensive, but because what the test finds can be.

What does ONECARS do about this before you get the car?

Every car we sell is checked on 34 points by ONEFIX, our own workshop on the same site at Plas Acton in Wrexham. The list is published at how we check our cars so you can see exactly what gets looked at. Where that check turns up work to do, the car is not handed over until ONEFIX has put it right — that rule sits in our system rather than in a sales promise.

Every car page carries the car's photographs, its full spec and its MOT history from the DVSA, test by test, with the mileage recorded at each test. The same history you would pull off GOV.UK yourself is already on the page, so you can read the car's past before you ring us about its future.

Afterwards, ONEFIX is still next door. It services, repairs and MOTs the cars we sell, which is the useful bit for running costs: the workshop that checked your car is the workshop that knows it. Every car also comes with a free three-month warranty on the engine and gearbox, up to 2,500 miles, with repairs done on the same site, and longer paid cover if you want it.

Are there extra costs on top of the asking price?

Not from us. ONECARS charges no admin fee — the price shown is the price paid. If you want to hold a car while you sort insurance or arrange a viewing, a reservation holds it for fourteen days, can be cancelled in that time for any reason with the fee refunded in full, and comes off the price if you go ahead. Delivery is free within 20 miles of Plas Acton on weekdays, in hourly slots, with the car checked, valeted and fuelled before it leaves us.

Which cars on the forecourt are the cheap ones to run?

Smaller engines in lighter cars, generally. Two on the forecourt now that fit the brief are the 2010 Volkswagen Polo 1.2 at £2,995 and the 2012 Vauxhall Astra 1.7 Club Ecoflex at £1,295. Check each car's page for its own tax band and MOT history, then see the rest at used cars.

A short checklist before you buy

1. Look up the car's vehicle tax band on GOV.UK.
2. Pull its MOT history and read the advisories, not just the passes.
3. Get an insurance quote on that exact car, with your postcode.
4. Ask when the next MOT is due.
5. Ask what the pre-sale check found and what was done about it.
6. Work out your real yearly mileage before you choose petrol or diesel.

Where to read next

What to check when you view a used car for the viewing itself, Questions to ask when buying a used car for the conversation, and what our warranty covers for what happens after. We are at Plas Acton Garage, 282 Chester Road, Wrexham LL12 8DU, open Monday to Friday 9 to 5 and Saturday 10 to 4 for viewings by appointment, or get in touch on 01978 356983.