2021 Audi A4 S Line prices

There are 25 used 2021 Audi A4 S Line cars for sale from UK dealers on AskCar, as of 8 November 2026. Typical asking price £17,000 (the median: half cost less, half cost more). The cheapest is £12,995. The middle half are priced between £16,600 and £18,000. Median mileage: about 49,000 miles.

Dealers lowered the asking price on more than a third of 2021 Audi A4 S Line cars: 10 of the 25 in the 14 days to 8 November 2026.

2021 Audi A4 S Line prices by engine and mileage

EngineAll mileagesUnder 20,000 miles20,000 to 40,000 miles40,000 to 60,000 miles60,000 miles or more
2.0 diesel£17,000Too few for saleToo few for saleToo few for saleToo few for sale

Typical asking prices are of 2021 Audi A4 S Line cars for sale on 8 November 2026, and are given only where at least 20 cars with a price are for sale.

2021 Audi A4 S Line against other years

A 2022 Audi A4 S Line car has a typical asking price of £19,000, as of 8 November 2026.

AskCar lists 1,461 used Audi A4 across the UK, from 964 dealerships.

As of 8 November 2026, AskCar lists 595,629 cars and vans from 12,891 UK dealerships, read daily from dealer websites: over 99% of UK dealer used car adverts. No dealer pays to be listed.

2021 Audi A4 S Line cars for sale now, page 1 of 2

This page picks out up to 10 cars in each of these groups: best value, cheapest, lowest mileage, recently reduced and newly advertised. A car in more than one group is listed in full once. The groups pick only from cars with photos and an AskCar estimate, priced at £500 or more and no more than 25% under that estimate. All 24 cars listed here meet these rules. Page 2 lists every other 2021 Audi A4 S Line car, cheapest first.

The AskCar estimate is our expected asking price for that one car, from its model, age, mileage and specification, using the 1,408 priced Audi A4 adverts on AskCar as of 8 November 2026. The figures on this page describe the cars advertised, not a valuation of every 2021 Audi A4 S Line.

Each car: year, make, model, engine and trim, power, gearbox, fuel, body, doors, colour; mileage; price and its changes; how the price compares with the AskCar estimate; emissions standard and ULEZ compliance where it holds; MOT; dealer and town; AskCar page. Each car's AskCar page has its full price history and cheaper cars like it.

This list leaves out 1 car whose advertised mileage is lower than the mileage recorded at its last MOT test.

Best value 2021 Audi A4 S Line: priced furthest below the AskCar estimate

These 10 are priced 1% to 5% under their AskCar estimate. Their asking prices run from £15,441 to £19,470.

Cheapest 2021 Audi A4 S Line: the lowest asking prices

These 10 are priced £12,995 to £16,895. They have covered 36,000 to 101,094 miles.

Lowest-mileage 2021 Audi A4 S Line

These 10 have covered 15,297 to 44,514 miles. Their asking prices run from £16,490 to £21,745.

Recently reduced 2021 Audi A4 S Line: the biggest price reductions in the 14 days to 8 November 2026

The dealer lowered the asking price on each of these 10 in the 14 days to 8 November 2026. Their reductions since AskCar first saw them run from £200 to £2,250.

Newly advertised 2021 Audi A4 S Line: first seen by AskCar in the 7 days to 8 November 2026

These 2 are the most recently advertised. Cars first seen on the same day are listed cheapest first.

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