2021 Mercedes-Benz C Class prices under £20,000

There are 71 used 2021 Mercedes-Benz C Class cars for sale under £20,000 from UK dealers on AskCar, as of 12 November 2026. Typical asking price £18,000 (the median: half cost less, half cost more). The cheapest is £12,990. The middle half are priced between £16,200 and £18,900. Median mileage: about 57,000 miles.

Dealers lowered the asking price on more than a third of 2021 Mercedes-Benz C Class cars under £20,000: 31 of the 71 in the 14 days to 12 November 2026.

AskCar lists 4,864 used Mercedes-Benz C Class across the UK, from 2,343 dealerships.

As of 12 November 2026, AskCar lists 596,362 cars and vans from 12,840 UK dealerships, read daily from dealer websites: over 99% of UK dealer used car adverts. No dealer pays to be listed.

2021 Mercedes-Benz C Class cars for sale now under £20,000, 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 69 cars listed here meet these rules. Page 2 lists every other 2021 Mercedes-Benz C Class car, cheapest first.

The AskCar estimate is our expected asking price for that one car, from its model, age, mileage and specification, using the 4,632 priced Mercedes-Benz C Class adverts on AskCar as of 12 November 2026. The figures on this page describe the cars advertised, not a valuation of every 2021 Mercedes-Benz C Class.

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 2 cars whose advertised mileage is lower than the mileage recorded at their last MOT test.

Best value 2021 Mercedes-Benz C Class: priced furthest below the AskCar estimate

These 10 are priced 10% to 21% under their AskCar estimate. Their asking prices run from £12,990 to £18,995.

Cheapest 2021 Mercedes-Benz C Class: the lowest asking prices

These 10 are priced £12,990 to £14,970. They have covered 58,000 to 96,000 miles.

Lowest-mileage 2021 Mercedes-Benz C Class

These 10 have covered 27,054 to 35,889 miles. Their asking prices run from £16,490 to £19,999.

Recently reduced 2021 Mercedes-Benz C Class: the biggest price reductions in the 14 days to 12 November 2026

The dealer lowered the asking price on each of these 10 in the 14 days to 12 November 2026. Their reductions since AskCar first saw them run from £1,400 to £5,005.

Newly advertised 2021 Mercedes-Benz C Class: first seen by AskCar in the 7 days to 12 November 2026

These 10 are the most recently advertised. Cars first seen on the same day are listed cheapest first.

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